[MISC] Merge update_tls_flag into update_endpoints

[dragomirp]

Early setting of the tls flags can cause errors when setting too early. E.g.

 Traceback (most recent call last):
  File "/var/lib/juju/agents/unit-postgresql-0/charm/./src/charm.py", line 1952, in <module>
    main(PostgresqlOperatorCharm)
  File "/var/lib/juju/agents/unit-postgresql-0/charm/venv/ops/__init__.py", line 343, in __call__
    return _main.main(charm_class=charm_class, use_juju_for_storage=use_juju_for_storage)
  File "/var/lib/juju/agents/unit-postgresql-0/charm/venv/ops/_main.py", line 543, in main
    manager.run()
  File "/var/lib/juju/agents/unit-postgresql-0/charm/venv/ops/_main.py", line 529, in run
    self._emit()
  File "/var/lib/juju/agents/unit-postgresql-0/charm/venv/ops/_main.py", line 518, in _emit
    _emit_charm_event(self.charm, self.dispatcher.event_name, self._juju_context)
  File "/var/lib/juju/agents/unit-postgresql-0/charm/venv/ops/_main.py", line 134, in _emit_charm_event
    event_to_emit.emit(*args, **kwargs)
  File "/var/lib/juju/agents/unit-postgresql-0/charm/venv/ops/framework.py", line 347, in emit
    framework._emit(event)
  File "/var/lib/juju/agents/unit-postgresql-0/charm/venv/ops/framework.py", line 857, in _emit
    self._reemit(event_path)
  File "/var/lib/juju/agents/unit-postgresql-0/charm/venv/ops/framework.py", line 947, in _reemit
    custom_handler(event)
  File "/var/lib/juju/agents/unit-postgresql-0/charm/lib/charms/tempo_coordinator_k8s/v0/charm_tracing.py", line 735, in wrapped_function
    return callable(*args, **kwargs)  # type: ignore
  File "/var/lib/juju/agents/unit-postgresql-0/charm/./src/charm.py", line 958, in _on_leader_elected
    self.update_config()
  File "/var/lib/juju/agents/unit-postgresql-0/charm/lib/charms/tempo_coordinator_k8s/v0/charm_tracing.py", line 735, in wrapped_function
    return callable(*args, **kwargs)  # type: ignore
  File "/var/lib/juju/agents/unit-postgresql-0/charm/./src/charm.py", line 1712, in update_config
    self.postgresql_client_relation.update_tls_flag(
  File "/var/lib/juju/agents/unit-postgresql-0/charm/lib/charms/tempo_coordinator_k8s/v0/charm_tracing.py", line 735, in wrapped_function
    return callable(*args, **kwargs)  # type: ignore
  File "/var/lib/juju/agents/unit-postgresql-0/charm/src/relations/postgresql_provider.py", line 238, in update_tls_flag
    self.database_provides.set_tls(relation.id, tls)
  File "/var/lib/juju/agents/unit-postgresql-0/charm/lib/charms/data_platform_libs/v0/data_interfaces.py", line 1683, in set_tls
    self.update_relation_data(relation_id, ***"tls": tls***)
  File "/var/lib/juju/agents/unit-postgresql-0/charm/lib/charms/data_platform_libs/v0/data_interfaces.py", line 496, in wrapper
    return f(self, *args, **kwargs)
  File "/var/lib/juju/agents/unit-postgresql-0/charm/lib/charms/data_platform_libs/v0/data_interfaces.py", line 1407, in update_relation_data
    return self._update_relation_data(relation, data)
  File "/var/lib/juju/agents/unit-postgresql-0/charm/lib/charms/data_platform_libs/v0/data_interfaces.py", line 1632, in _update_relation_data
    raise PrematureDataAccessError(
charms.data_platform_libs.v0.data_interfaces.PrematureDataAccessError: Premature access to relation data, update is forbidden before the connection is initialized.

This PR merges update_tls_flag into update_endpoints to reuse the checks for PrematureDataAccessError

[codecov]

Codecov Report

Attention: Patch coverage is 60.00000% with 4 lines in your changes missing coverage. Please review.

Project coverage is 71.40%. Comparing base (1acd0ee) to head (0eeb3b5).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/charm.py	50.00%	1 Missing and 1 partial ⚠️
src/relations/postgresql_provider.py	66.66%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #669      +/-   ##
==========================================
+ Coverage   71.31%   71.40%   +0.08%     
==========================================
  Files          13       13              
  Lines        3193     3189       -4     
  Branches      476      475       -1     
==========================================
  Hits         2277     2277              
+ Misses        800      797       -3     
+ Partials      116      115       -1     

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[dragomirp]

Endpoints will be updated anyway

[dragomirp]

Seen fail on ci:

   File "/var/lib/juju/agents/unit-postgresql-gcp-1/charm/./src/charm.py", line 825, in members_ips
    return set(json.loads(self._peers.data[self.app].get("members_ips", "[]")))
AttributeError: 'NoneType' object has no attribute 'data'