Improvement for MaterializeMySQL: Exception for Insufficient MySQL Sync Privileges

Why it matters

This feature ensures that users are immediately notified if the MySQL user configured for sync in MaterializeMySQL does not have the correct privileges, preventing silent failures or incomplete data synchronization. It improves reliability and diagnostics by enforcing privilege checks.

How to use it

When using the experimental MaterializeMySQL engine, ensure that the MySQL sync user has the required synchronization privileges. If the privileges are insufficient, ClickHouse will throw an exception during sync initialization, alerting you to fix the user permissions before proceeding.