Remove numbering on sub-section slide

I am preparing my thesis defense slides and I can't remove the numbering from the slide that displays the name of the sub-section (slide 5 and 7). I have tried to modify the metropolis template I am using, but without success. Is there anyone who knows how to do this?

Thank you very much for your help!

 \documentclass{beamer}
\usetheme[progressbar=frametitle, sectionpage=progressbar, subsectionpage=progressbar, block=fill]{metropolis}
\setbeamertemplate{footline}{}
\setbeamertemplate{navigation symbols}{%
    \ifnum\insertframenumber>0
         \normalsize\insertframenumber%
    \fi%
}
 
\title{Title}
\subtitle{Sub-title}
\date{\today}
\author{author}
\institute{institute}
 
 
\AtBeginSection[]
{
    \setbeamertemplate{navigation symbols}{}
    \frame[plain,c,noframenumbering]{
        \sectionpage
        \tableofcontents[currentsection,subsectionstyle=hide]}
    \setbeamertemplate{navigation symbols}{\normalsize\insertframenumber}
}
 
\makeatletter
 
\setbeamertemplate{section in toc}[sections numbered]
\setbeamertemplate{subsection in toc}[subsections numbered]
 
\makeatother
 
\begin{document}
  \maketitle
 
\section{First section}
 
\begin{frame}
Content 
\end{frame}
 
\section{Second section}
\subsection{First sub section}
\begin{frame}
Content 
\end{frame}   
 
\subsection{Second sub section}
\begin{frame}
Content 
\end{frame} 
 
 
\section{Third section}
\end{document}