Exit admin mode properly on iosxr_config (#39594)

Fixes #38811

When using 'admin' in iosxr-config, we need to pass an end
to config terminal session but also pass exit so we exit admin
mode.

lib/ansible/module_utils/network/iosxr/iosxr.py

@@ -426,6 +426,8 @@ def load_config(module, command_filter, commit=False, replace=False,
         elif commit:
             commit_config(module, comment=comment)
             conn.edit_config('end')
+            if admin:
+                conn.edit_config('exit')
         else:
             conn.discard_changes()