treestatus: check for user authentication before require_auth0 API calls (Bug 1896642)

[cgsheeh]

In other parts of Lando, before making an API call that uses
the require_auth0 kwarg, we do an explicit check that the
user is authenticated and handle unauthenticated requests
appropriately. This was overlooked in implementing the Treestatus
UI and is resulting in errors in Sentry since we instead
only discover the missing credentials when making the request,
resulting in an unhandled exception. Add an explicit check
to each handler which makes an auth0_required API call.

[zzzeid]

There is still the issue of the incorrect validation that was causing the ValueError. We should file a separate bug for that and fix it as a P3.

[cgsheeh]

There is still the issue of the incorrect validation that was causing the ValueError. We should file a separate bug for that and fix it as a P3.

That validation is happening at the Flask-WTForms level. This PR will convert the issue of invalid input into that form handler from an un-authed bug to an authed bug, which should be enough to resolve this, at least until we move to Django-Lando. We create other FlaskForm instances without error handling in other parts of Lando FWIW.

[zzzeid]

There is still the issue of the incorrect validation that was causing the ValueError. We should file a separate bug for that and fix it as a P3.

That validation is happening at the Flask-WTForms level. This PR will convert the issue of invalid input into that form handler from an un-authed bug to an authed bug, which should be enough to resolve this, at least until we move to Django-Lando. We create other FlaskForm instances without error handling in other parts of Lando FWIW.

What I'm saying is that this ValueError appears to be new unhandled behaviour that is specific to the treestatus migration. As far as I can tell, no other endpoints appear to cause this error (including ones that initialize the form before validating it, similar to how this was before this PR). It should be tracked in a bug so we can fix it, either here or when it is ported to Django (hence P3). Validation errors should happen when form.is_valid() is called, not when it is initialized.