While investigating https://docs.google.com/document/d/15dUeSfwUskCzuXt7Xbp6uAebQmjK9h6f4Mw_C-WErgw/edit?tab=t.0#heading=h.iiw5d9gpn1f0, I realized a feature flag that was previously set at a tenant level cannot be unset.

1. If the feature flag is set to "null", it can cause "feature flag ... type mismatched" errors from the code in src/streams/exec/tenant_feature_flags.cppand src/streams/exec/feature_flag.cpp.

1. If the feature flag entry is removed from the tenant/project/global config... the engine will retain the last value of the flag.

We should fix one or both of these things.

To repro this issue on the engine side:

• Set a feature flag, and start a processor.
• The user updateFeatureFlags command to "unset" the feature flag, i.e. set it to null/missing.