refactor(widgets): migrateGTK imports to fabric.utils

Migrate GTK-related imports from gi.repository to fabric.utils and remove outdated require_version calls.

- Remove redundant gi.require_version declarations
- Replace gi.repository imports with fabric.utils equivalents
- Align import ordering for consistency

widgets/custom_image.py

@@ -2,7 +2,7 @@ import math
 from typing import cast
 
 import cairo
-from gi.repository import Gtk
+from fabric.utils import Gtk
 
 from fabric.widgets.image import Image