Draft: gui_utils.py fix error in select function (#19539)

* Draft: gui_utils.py fix error in select function

PR #18795 changed the select function to also handle tuples. This PR adds a check to ensure the referenced objects in the tuple still exist before calling `Gui.Selection.addSelection()`.

src/Mod/Draft/draftutils/utils.py

@@ -389,6 +389,14 @@ def tolerance():
     return 10 ** -precision()
 
 
+def is_deleted(obj):
+    """Return `True` if obj is deleted."""
+    try:
+        return not obj.isAttachedToDocument()
+    except:
+        return True
+
+
 def get_real_name(name):
     """Strip the trailing numbers from a string to get only the letters.