repo-utils: Drop stripping .desktop suffixes from appstream cids

This will pass the exact appstream component ID to copy_icon

This was introduced in 7dd92d8a9b to
handle appstream component IDs that ended in two `.desktop` suffixes.

Recent analysis of appstream data shows that at least on Flathub no such
appstream cid exist anymore and Telegram now has component ID
`com.telegram.desktop`.

With the switch to libappstream, appstreamcli-compose produces icons in
`share/app-info/flatpak` named by the appstream component ID instead of
the `$FLATPAK_ID` used by appstream-glib. This causes applications whose
`$FLATPAK_ID` does not end with `.desktop` but their appstream-component
ID ends in `.desktop` ie. `$FLATPAK_ID != appstream-cid` to loose icons
from the appstream ostree ref as `copy_icon` was being fed the id
without `.desktop` but icons were created by appstreamcli
with `.desktop` in them.

This will avoid adding anymore ID heuristics/workarounds on either side,
per the discussion in [1].

An application with the `$FLATPAK_ID` `com.telegram.desktop` and the
appstream ID `com.telegram.desktop.desktop` will be broken with this
change but such dual `.desktop` IDs are non existent and should be fixed
individually or be blocked on an app store level.

[1]: https://github.com/flathub/flathub/issues/4222

common/flatpak-repo-utils.c

@@ -3232,9 +3232,6 @@ extract_appstream (OstreeRepo        *repo,
               continue;
             }
 
-          if (g_str_has_suffix (component_id_suffix, ".desktop"))
-            component_id_suffix[strlen (component_id_suffix) - strlen (".desktop")] = 0;
-
           if (!copy_icon (component_id_text, icons_dir, repo, size1_mtree, "64x64", &my_error))
             {
               g_print (_("Error copying 64x64 icon for component %s: %s\n"), component_id_text, my_error->message);