feat!: remove appendix redefinition

Remove the custom appendix modification, as per the suggestion in https://github.com/matze/mtheme/pull/342 by @kno10.

src/beamerouterthememoloch.dtx

@@ -204,24 +204,6 @@
 %    \end{macrocode}
 % \end{macro}
 %
-%
-%
-% \begin{macro}{appendix}
-%    Removes page numbering and per-slide progress bars when |\appendix| is
-%    called. This makes it easier to include additional ``backup slides'' at
-%    the end of the presentation, especially in conjunction with the package
-%    |appendixnumberbeamer|.
-% \begin{macrocode}
-\AtBeginDocument{%
-  \apptocmd{\appendix}{%
-    \pgfkeys{%
-      /moloch/outer/.cd,
-      numbering=none,
-      progressbar=none}
-  }{}{}
-}
-%    \end{macrocode}
-% \end{macro}
 % \subsubsection{Process package options}
 %
 %    \begin{macrocode}