Connection without specifying catalog name in connection string causes an error

從 src/databricks/sqlalchemy/base.py 第 278 行附近開始，追蹤當連線字串省略 catalog 時 get_table_names 如何處理 catalog。使用一個 schema 和明確的 catalog 重現 SHOW VIEWS 失敗，然後驗證 metadata 檢查可以針對該 catalog，而不會產生 None catalog。

Hello,
I'm trying to create an engine connection which could manage multiple catalogs at once

connection_uri = "databricks://token:XXXXXX@DB_HOST?http_path=/sql/1.0/warehouses/DWH_ID"
engine = create_engine(connection_uri, future=True)
meta_inspector = inspect(self.engine)

Later when calling for example
tables = meta_inspector.get_table_names('test_schema')
I get the following error

backend-1  | sqlalchemy.exc.DatabaseError: (databricks.sql.exc.ServerOperationError) Fail to execute the command as the target schema `None.test_schema` is not in the current catalog. Please set the current catalog with 'USE CATALOG None' first.
backend-1  | [SQL: SHOW VIEWS FROM `None`.`test_schema`]

After further inspection I found the current method being called:
https://github.com/databricks/databricks-sql-python/blob/62eb1d407ab03fc2c57a6626bec2173dbdd8bbb3/src/databricks/sqlalchemy/base.py#L278

It could be fixed with adding on Line 278 the following:
_target_catalog = kwags.get("catalog") or self.catalog
and referencing the catalog name in the method get_table_names
tables = meta_inspector.get_table_names(schema='test_schema',catalog='test_catalog')

NOTE : I'm avoiding creating a different engine for every catalog due to slow response from Databricks
I'm hesitant in opening a PR for this as it's not well tested and I'm not sure if there is an alternative to what i'm trying to achieve , so any feedback would be great !