This can happen in some situations if we check feature flags before
the application settings object has been initialized. If that happens,
we will try to cache the flag states in redis, which causes redis
metrics to be monitored, which in turn depends on the application
settings. If there is a flag check at the DB transaction level (or at
any other point in this chain) we get infinite recursion, which slowly
causes the stack to overflow (slowly, because there is IO at almost
every layer of the stack).

Instead, we mark when we try to create application settings, and if
the method is re-entered, we bail and fall-back to in-memory application
settings.

Changelog: fixed