v.24.11Improvement

Check Default Database Presence After Authorization Fixes #71097 and #71140

Check if default database is present after authorization. Fixes #71097. #71140 (Konstantin Bogdanov).
Adds a check to verify the presence of the default database after user authorization in ClickHouse.

Why it matters

This feature addresses an issue where the default database might not exist after a user logs in, which could lead to unexpected errors or confusion. By ensuring the default database is present, it improves stability and user experience in database management.

How to use it

The check is performed automatically after user authorization, requiring no additional configuration or commands from the user.