[Yoga-Focal] Octavia fails with hook failed: "identity-service-relation-changed"

In testrun https://solutions.qa.canonical.com/testruns/testRun/80737dc2-7593-488a-8fbe-f19a39b7c622, which is yoga-focal, one octavia unit fails:

```
octavia/0* error idle 0/lxd/7 10.246.165.164 9876/tcp hook failed: "identity-service-relation-changed"
  filebeat/69 active idle 10.246.165.164 Filebeat ready.
  hacluster-octavia/0* active idle 10.246.165.164 Unit is ready and clustered
  landscape-client/70 maintenance idle 10.246.165.164 Need computer-title and juju-info to proceed
  logrotated/63 active idle 10.246.165.164 Unit is ready.
  nrpe/77 active idle 10.246.165.164 icmp,5666/tcp Ready
  octavia-mysql-router/0* active idle 10.246.165.164 Unit is ready
  octavia-ovn-chassis/0* active idle 10.246.165.164 Unit is ready
  prometheus-grok-exporter/69 active idle 10.246.165.164 9144/tcp Unit is ready
  public-policy-routing/41 active idle 10.246.165.164 Unit is ready
  telegraf/70 active idle 10.246.165.164 9103/tcp Monitoring octavia/0 (source version/commit 0380c15)
```

In the unit logs we see:
```
Traceback (most recent call last):
  File "/var/lib/juju/agents/unit-octavia-0/.venv/lib/python3.8/site-packages/charms/reactive/__init__.py", line 74, in main
    bus.dispatch(restricted=restricted_mode)
  File "/var/lib/juju/agents/unit-octavia-0/.venv/lib/python3.8/site-packages/charms/reactive/bus.py", line 390, in dispatch
    _invoke(other_handlers)
  File "/var/lib/juju/agents/unit-octavia-0/.venv/lib/python3.8/site-packages/charms/reactive/bus.py", line 359, in _invoke
    handler.invoke()
  File "/var/lib/juju/agents/unit-octavia-0/.venv/lib/python3.8/site-packages/charms/reactive/bus.py", line 181, in invoke
    self._action(*args)
  File "/var/lib/juju/agents/unit-octavia-0/charm/reactive/octavia_handlers.py", line 279, in init_db
    octavia_charm.db_sync()
  File "/var/lib/juju/agents/unit-octavia-0/.venv/lib/python3.8/site-packages/charms_openstack/charm/core.py", line 845, in db_sync
    subprocess.check_call(self.sync_cmd)
  File "/usr/lib/python3.8/subprocess.py", line 364, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['sudo', 'octavia-db-manage', 'upgrade', 'head']' returned non-zero exit status 1.
```

The mysql-router of the unit is active, so I'm not sure where the db error comes from.

Logs, configs, and crashdumps can be found here:
https://oil-jenkins.canonical.com/artifacts/80737dc2-7593-488a-8fbe-f19a39b7c622/index.html