Idempotent creation of availability zones broken: oslo_db.exception.DBDuplicateEntry: (pymysql.err.IntegrityError) (1062, "Duplicate entry 'nova-False' for key 'availability_zones.az_name_uc'")

[Goutham Pacha Ravi]

Description
===========
In the CI, during the "2023.1/Antelope" cycle, we frequently run into an issue where the idempotent creation of AZ [1][2][3] fails during service creation. This often affects the manila-data service on the CI given the way we setup AZ based services. We create the scheduler service first, then setup backend-specific share-manager services and then the manila-data service. The backend-specific share manager services are always set to separate AZs to aid our testing.

Error log: https://paste.openstack.org/show/bHCkymE3CreECWAeauqV/

Steps to reproduce
==================
Reproducible by setting up devstack with Manila as well - with any share backend.

The issues started occurring on sporadic jobs, curiously with the dummy driver configured, after we merged https://review.opendev.org/c/openstack/manila/+/856144/4/manila/db/sqlalchemy/models.py

[1] https://opendev.org/openstack/manila/src/commit/f075b1bd7d01516818693c930f9974227de50363/manila/db/sqlalchemy/api.py#L643
[2] https://opendev.org/openstack/manila/src/commit/f075b1bd7d01516818693c930f9974227de50363/manila/db/sqlalchemy/api.py#L5710-L5711
[3] https://opendev.org/openstack/manila/src/commit/f075b1bd7d01516818693c930f9974227de50363/manila/db/sqlalchemy/api.py#L5746-L5750

[Vida Haririan (vhariria)]

See additional related discussions at https://meetings.opendev.org/meetings/manila/2023/manila.2023-03-02-15.00.log.html