UV: Add "Invert Pins" to the menu in the uv editor

Thanks Robert Rioux for the suggestion.

Pull Request: https://projects.blender.org/blender/blender/pulls/109187

scripts/startup/bl_ui/space_image.py

@@ -428,6 +428,7 @@ class IMAGE_MT_uvs(Menu):
 
         layout.operator("uv.pin").clear = False
         layout.operator("uv.pin", text="Unpin").clear = True
+        layout.operator("uv.pin", text="Invert Pins").invert = True
 
         layout.separator()