[Flow202][keyserver][skip-ci] [4/x] Address type error in rescindPushNotifs
Summary:
The new version of Flow caught a type error here! It was introduced in D8706; more details in my comment there.
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 D9851
Test Plan: Confirm the Flow errors go away
Reviewers: michal
Reviewed By: michal
Subscribers: tomek
Differential Revision: https://phab.comm.dev/D9852