wlroots: Fix the build by not copying the library to $examples

Copying libwlroots isn't required anymore since the library runpath
of the example binaries now correctly references $out/lib anyway.

Fix #95205.

pkgs/development/libraries/wlroots/default.nix

···
 
   mesonFlags = [ "-Dlogind-provider=systemd" ];
 
-  postInstall = ''
-    # Copy the library to $examples
-    mkdir -p $examples/lib
-    cp -P libwlroots* $examples/lib/
-  '';
-
   postFixup = ''
     # Install ALL example programs to $examples:
     # screencopy dmabuf-capture input-inhibitor layer-shell idle-inhibit idle