Feature flag override no longer sticks on updateFlags merge

1.388.2

Patch Changes

• #3870 5edfee1 Thanks @turnipdabeets! - Fix updateFlags(flags, payloads, { merge: true }) baking an active feature flag override into the stored flags. The merge now seeds from the raw stored flags rather than the override-applied values, so clearing the override afterwards correctly restores the original flag. (2026-06-17)