[keyserver] include targetMessageID in fetchCollapsableNotifs query

Summary: included targetMessageID in fetchCollapsableNotifs query. Was doing some final tests of message liking and noticed an invariant going off since targetMessageID was not included in this query

Test Plan:
After these changes the following invariant message no longer appears in the logs

Reviewers: atul, tomek

Reviewed By: atul, tomek

Subscribers: ashoat, tomek, atul

Differential Revision: https://phab.comm.dev/D5959