Separating this out because I had to make some more significant changes.
The new version of Flow isn't able to interpret that filtering on RawMessageInfo.type will result in an array with a different type param.
NOTE: CI will fail on this diff. I considered the possibility of fixing Flow errors BEFORE upgrading Flow, but it wasn't possible... in some cases, the fixes to support the new version of Flow caused errors in the old version. I could have hidden these type errors with $FlowFixMe lines and then later revert those, but that seemed like too much busy work.
Depends on D10010