[Flow202][keyserver][skip-ci] [24/x] Address missing-local-annot type errors
Summary:
The new version of Flow wants more annotations for function and member definitions. This diff adds all of the required annotations to the keyserver codebase necessary to clear all missing-local-annot errors. This is the keyserver equivalent of D9771 (web) and D9697 (lib).
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 D9872
Test Plan: Confirm the Flow errors go away
Reviewers: tomek
Reviewed By: tomek
Differential Revision: https://phab.comm.dev/D9873