fix(sqllab): Allow clear on schema and catalog (#32515)

(cherry picked from commit 4c3aae7)

Author: justinpark

superset-frontend/src/components/DatabaseSelector/index.tsx

@@ -392,6 +392,7 @@ export default function DatabaseSelector({
         options={catalogOptions}
         showSearch
         value={currentCatalog || undefined}
+        allowClear
       />,
       refreshIcon,
     );
@@ -418,6 +419,7 @@ export default function DatabaseSelector({
         options={schemaOptions}
         showSearch
         value={currentSchema}
+        allowClear
       />,
       refreshIcon,
     );

superset/commands/dataset/importers/v1/utils.py

@@ -102,6 +102,7 @@ def validate_data_uri(data_uri: str) -> None:
     raise DatasetForbiddenDataURI()
 
 
+# pylint: disable=too-many-branches
 def import_dataset(
     config: dict[str, Any],
     overwrite: bool = False,