fix(meta): get_permitted_fields with no field-columns (backport #20401)…

… (#20404)

Co-authored-by: gavin <gavin18d@gmail.com>
Co-authored-by: Suraj Shetty <13928957+surajshetty3416@users.noreply.github.com>
fix(meta): get_permitted_fields with no field-columns (#20401)

frappe/model/__init__.py

@@ -190,6 +190,10 @@ def get_permitted_fields(
 
 	if doctype in core_doctypes_list:
 		return valid_columns
+
+	# DocType has only fields of type Table (Table, Table MultiSelect)
+	if set(valid_columns).issubset(default_fields):
+		return valid_columns
 
 	permitted_fields = meta.get_permitted_fieldnames(parenttype=parenttype, user=user)