nixos/telepathy: Remove GNOME remnants

GNOME Shell 46 dropped the telepathy support so we no longer need to add the typelib to session path.
https://gitlab.gnome.org/GNOME/gnome-shell/-/commit/c5ec3e45e4562246ba65ac2ca19eadfdfee627ca

Looking at Debian code search, no packages other than Polari should need the typelib from path anyway, and Polari already gets it from a wrapper:
https://codesearch.debian.net/search?q=TelepathyGLib+-package%3Atelepathy-glib+-package%3Asugar+-path%3Avala&literal=0

Also unmaintain as it is no longer used by GNOME.

The daemon components are needed by lomiri and polari:
https://codesearch.debian.net/search?q=org.freedesktop.Telepathy.MissionControl5%7Corg.freedesktop.Telepathy.AccountManager%7C%5Cbmc-tool%5Cb%7Cmc-wait-for-name&literal=0

Author: jtojnar

nixos/modules/services/desktops/telepathy.nix

@@ -8,7 +8,7 @@
 {
 
   meta = {
-    maintainers = lib.teams.gnome.members;
+    maintainers = [ ];
   };
 
   ###### interface
@@ -37,11 +37,6 @@
     environment.systemPackages = [ pkgs.telepathy-mission-control ];
 
     services.dbus.packages = [ pkgs.telepathy-mission-control ];
-
-    # Enable runtime optional telepathy in gnome-shell
-    services.xserver.desktopManager.gnome.sessionPath = with pkgs; [
-      telepathy-glib
-    ];
   };
 
 }