refactor(database): use SupersetResultSet on SqlaTable.get_df() (#10707)

* refactor(database): use SupersetResultSet on SqlaTable.get_df()

* lint

* change cypress test

superset/db_engine_specs/postgres.py

@@ -53,7 +53,9 @@ class PostgresBaseEngineSpec(BaseEngineSpec):
     }
 
     @classmethod
-    def fetch_data(cls, cursor: Any, limit: int) -> List[Tuple[Any, ...]]:
+    def fetch_data(
+        cls, cursor: Any, limit: Optional[int] = None
+    ) -> List[Tuple[Any, ...]]:
         cursor.tzinfo_factory = FixedOffsetTimezone
         if not cursor.description:
             return []