Return empty string as label if we don't have keywords (#13656)

Author: giohappy

geonode/base/fields.py

@@ -25,4 +25,5 @@ def label_from_instance(self, obj):
         # Note: Not using .get() because filter()[0] is used in original
         # code. The hard-coded language is currently used throughout
         # geonode.
-        return obj.keyword.first().label
+        first_keyword = obj.keyword.first()
+        return first_keyword.label if first_keyword else ""