Revert "tdesktop: fix for loading libXcursor"

This hack breaks programs executed by telegram, and appears not to be
necessary any longer.

Tracing shows neither tdesktop nor its dependencies actually link
against libXcursor, load it via dlopen, or call into it.

This reverts commit 910b2be5ac08264311123d3add6d81e8e6fd05b8.

Updates: #181176

pkgs/applications/networking/instant-messengers/telegram/telegram-desktop/default.nix

···
 , libthai
 , libdatrie
 , xdg-utils
-, xorg
 , libsysprof-capture
 , libpsl
 , brotli
···
     wrapProgram $out/bin/telegram-desktop \
       "''${gappsWrapperArgs[@]}" \
       "''${qtWrapperArgs[@]}" \
-      --prefix LD_LIBRARY_PATH : "${xorg.libXcursor}/lib" \
       --suffix PATH : ${lib.makeBinPath [ xdg-utils ]}
   '';