Prevent hyperlink tagging being added as an undo action

When the mouse hovers over a link in the note editor it is
highlighted. This was stacked as an undoable action and as a
result clicking the undo button sometimes had no noticeable
effect.

Fixes #13267.

gramps/gui/widgets/undoablestyledbuffer.py

@@ -112,6 +112,8 @@ def undo_disabled(self):
             self.not_undoable_action = oldflag
 
     def on_tag_insert_undoable(self, buffer, tag, start, end):
+        if tag.get_property("name") == "hyperlink":
+            return
         if not self.undo_in_progress:
             self._empty_redo_stack()
         if self.not_undoable_action: