Reduce level of errors that should be warnings

[tobias-wilfert]

As part of a recent incident investigation it became clear that there are some spammy error logs in google. The reason these are errors is that this currently allows them to go to Sentry.

As such the fix for this would be to change it such that warnings also go to Sentry and reduce the severity of everything that should not be an error in google logs (but is still interesting to have in Sentry) to warning.