Graphic in line with listing code name part 2

Question

This question is building from the solution given by TeXnician that can be found here. Note that this original design was devised by Harvey Sheppard.

I wanted to adjust the position of the graphic that appears next to the listing heading so that the graphic appears vertically centered with the text like this:

Here is TeXnician's original solution:

\documentclass[a4paper, 10pt, oneside, fleqn, openright]{report}
\usepackage[no-math]{fontspec}

\usepackage{polyglossia}
\setdefaultlanguage{french}
\setotherlanguages{english}

\newcommand{\codeimg}{\includegraphics[scale=0.05]{example-image-a}}

\usepackage{calc}
\usepackage[usenames,dvipsnames,svgnames,table]{xcolor}
\usepackage{pdfpages,graphicx}
\usepackage{mdframed}
\usepackage{listings}
\definecolor{light-gray}{gray}{0.92}

\definecolor{mainColor}{RGB}{211, 47, 47} % some dark red

\renewcommand\lstlistingname{Code}
\lstset{
    language=Python,
    numbers=left,
    numbersep= 7mm,
    numberstyle=\color{Black},
    stepnumber=1,
    tabsize=3,
    breakatwhitespace=false,
    breaklines=true,
    captionpos=b,
    basicstyle=\color{Black}\ttfamily,
    commentstyle=\color{LimeGreen},
    keywordstyle=\color{BurntOrange}\bfseries,
    stringstyle=\color{WildStrawberry},
    keywords={var, func, extends},
    frame=leftline,
    framesep=0mm,
    xleftmargin=3mm,% marge ajouté à gauche du tableau (à configurer en dernier pour l'alignement global du tableau)
    framesep=2mm, %distance texte bord du cadre (limite de la background color)
    framerule=0mm,
    abovecaptionskip=5mm,
    aboveskip=\baselineskip,
    belowskip=\baselineskip
}

\usepackage{tcolorbox}
\tcbuselibrary{skins,breakable,listings}
\newtcblisting[use counter=lstlisting]{codeblock}[2][]{%
        enhanced,noparskip,breakable,colback=light-gray,colframe=DarkSlateGray,opacitybacktitle=.8,%
        fonttitle=\bfseries,before upper={\hspace*{-1em}\includegraphics[height=\baselineskip]{example-image-a}~#2},%
        title after break={\centering\footnotesize\itshape\strut\lstlistingname~\thelstlisting~--~continued},%
        listing only,listing options={xleftmargin=-1mm},after upper={\centering\strut\lstlistingname~\thelstlisting:~#2},
        frame hidden,arc=0pt,outer arc=0pt,boxrule=0pt,frame code={\draw[gray,line width=2mm] ([xshift=-0.5pt]frame.north west) -- ([xshift=-0.5pt]frame.south west);},#1}

\begin{document}

\begin{codeblock}{Les bases de GDScript}
var nombreDeGardes = 4 #déclaration d'une variable
nombreDeGardes = plusDeux(nombreDeGardes) #appel d'une fonction avec la variable nombreDeGardes passée en paramètre

func maFonction(): #cette ligne déclare une nouvelle fonction nommée maFonction
    var variable1 = 7 #nouvelle variable dont la valeur est 7
    variable2 = ['un', 'deux', 'trois'] #variable assignée à un tableau contenant trois chaines de caractères

func plusDeux(argument1):
    return argument1 + 2
\end{codeblock}
\end{document}  

Answer 1

Use \raisebox{vertical shift}[extension above baseline][extension below baseline]{shifted contents}. In your example:

before upper={\hspace*{-1em}\raisebox{-.2\baselineskip}[0pt][0pt]{\includegraphics[height=\baselineskip]{example-image-a}}~#2}

\documentclass[a4paper, 10pt, oneside, fleqn, openright]{report}
\usepackage[no-math]{fontspec}

\usepackage{polyglossia}
\setdefaultlanguage{french}
\setotherlanguages{english}

\newcommand{\codeimg}{\includegraphics[scale=0.05]{example-image-a}}

\usepackage{calc}
\usepackage[usenames,dvipsnames,svgnames,table]{xcolor}
\usepackage{pdfpages,graphicx}
\usepackage{mdframed}
\usepackage{listings}
\definecolor{light-gray}{gray}{0.92}

\definecolor{mainColor}{RGB}{211, 47, 47} % some dark red

\renewcommand\lstlistingname{Code}
\lstset{
    language=Python,
    numbers=left,
    numbersep= 7mm,
    numberstyle=\color{Black},
    stepnumber=1,
    tabsize=3,
    breakatwhitespace=false,
    breaklines=true,
    captionpos=b,
    basicstyle=\color{Black}\ttfamily,
    commentstyle=\color{LimeGreen},
    keywordstyle=\color{BurntOrange}\bfseries,
    stringstyle=\color{WildStrawberry},
    keywords={var, func, extends},
    frame=leftline,
    framesep=0mm,
    xleftmargin=3mm,% marge ajouté à gauche du tableau (à configurer en dernier pour l'alignement global du tableau)
    framesep=2mm, %distance texte bord du cadre (limite de la background color)
    framerule=0mm,
    abovecaptionskip=5mm,
    aboveskip=\baselineskip,
    belowskip=\baselineskip
}

\usepackage{tcolorbox}
\tcbuselibrary{skins,breakable,listings}
\newtcblisting[use counter=lstlisting]{codeblock}[2][]%
  {enhanced,noparskip,breakable,colback=light-gray,
   colframe=DarkSlateGray,opacitybacktitle=.8,fonttitle=\bfseries,
   before upper={\hspace*{-1em}\raisebox{-3pt}[0pt][0pt]{\includegraphics[height=\baselineskip]{example-image-a}}~#2},
   title after break={\centering\footnotesize\itshape\strut\lstlistingname~\thelstlisting~--~continued},
   listing only,listing options={xleftmargin=-1mm},
   after upper={\centering\strut\lstlistingname~\thelstlisting:~#2},
   frame hidden,arc=0pt,outer arc=0pt,boxrule=0pt,
   frame code={\draw[gray,line width=2mm] ([xshift=-0.5pt]frame.north west) -- ([xshift=-0.5pt]frame.south west);},
   #1
  }

\begin{document}

\begin{codeblock}{Les bases de GDScript}
var nombreDeGardes = 4 #déclaration d'une variable
nombreDeGardes = plusDeux(nombreDeGardes) #appel d'une fonction avec la variable nombreDeGardes passée en paramètre

func maFonction(): #cette ligne déclare une nouvelle fonction nommée maFonction
    var variable1 = 7 #nouvelle variable dont la valeur est 7
    variable2 = ['un', 'deux', 'trois'] #variable assignée à un tableau contenant trois chaines de caractères

func plusDeux(argument1):
    return argument1 + 2
\end{codeblock}
\end{document}