Performance: Explore alternative to fetching all schemas in base.py

Since we already know the schema name, we could potentially check whether it exists rather than fetching all schemas and then comparing:
```
def _get_schemas_list(
self,
database_name: str | None = None,
) -> list[str]:
"""Return a list of all tables in the database."""
inspector: Inspector = sqlalchemy.inspect(self.get_sql_engine())
database_name = database_name or self.database_name
found_schemas = inspector.get_schema_names()
return [
found_schema.split(".")[-1].strip('"')
for found_schema in found_schemas
if "." not in found_schema
or (found_schema.split(".")[0].lower().strip('"') == database_name.lower())
]
```