Fix a data race between the dns_zone and dns_catz modules

Arаm Sаrgsyаn requested to merge 4132-catz-data-race-in-db.c into main

The dns_zone_catz_enable_db() and dns_zone_catz_disable_db() functions can race with similar operations in the catz module because there is no synchronization between the threads.

Add catz functions which use the view's catalog zones' lock when registering/unregistering the database update notify callback, and use those functions in the dns_zone module, instead of doing it directly.

Closes #4132 (closed)

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