feat: add extension point for workspace home page (#21033)

* updates to allow insertion of workspace home sidescroll/table UI

* fix types

* fix User type import

* add welcome message to ui registry

* add extra fields to individual chart/query GET results (for workspace home required info)

* update list view card to support a subtitle

* add id to individual chart fetch

* update chart api test

* another test fix

* fix saved query test

* update extension types + insert point

* fix typing

* fix type name

tests/integration_tests/queries/saved_queries/api_tests.py

@@ -525,8 +525,10 @@ class TestSavedQueryApi(SupersetTestCase):
             "label": "label1",
         }
         data = json.loads(rv.data.decode("utf-8"))
+        self.assertIn("changed_on_delta_humanized", data["result"])
         for key, value in data["result"].items():
-            assert value == expected_result[key]
+            if key not in ("changed_on_delta_humanized",):
+                assert value == expected_result[key]
 
     def test_get_saved_query_not_found(self):
         """