Add Access Check for System Drop Filesystem Cache with ON CLUSTER Support

Why it matters

This feature enhances security by restricting the ability to drop the filesystem cache to users with proper permissions. It also enables cluster-wide cache drops, improving operational efficiency in distributed environments.

How to use it

Users must have the necessary access rights to execute the system drop filesystem cache command. To run it across all nodes in a cluster, use the ON CLUSTER syntax, for example:

SYSTEM DROP FILESYSTEM CACHE ON CLUSTER cluster_name;