Connection without specifying catalog name in connection string causes an error

从 src/databricks/sqlalchemy/base.py 第 278 行附近开始，跟踪当连接字符串省略 catalog 时 get_table_names 如何处理 catalog。使用一个 schema 和显式 catalog 重现 SHOW VIEWS 失败，然后验证 metadata 检查可以针对该 catalog，而不会生成 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 !