Add append_oplog_note_mongos.js to backports_required_for_multiversion_tests.yml

Since we've decided to now backport the sharded cluster version of the append_oplog_note command all the way to 4.2, we should make use of the backports_required_for_multiversion_tests.yml file to allow for future multiversion testing.

This ticket should also remove the requires_fcv_60 tag from the test.