fix(#9381): accept_case_reports transition fails to persist doc changes

[shivv23]

Summary

The accept_case_reports transition's onMatch function returns the result of silenceRegistrations(), which resolves to undefined. The transitions framework treats falsy return values as "no changes," so document modifications (messages, place_uuid) are never persisted to the database.

Changes

• Appended .then(() => true) to the silenceRegistrations call to ensure a truthy return value when the transition completes successfully.
• Updated the unit test to assert the truthy return value.

Testing

• All 14 accept_case_reports transition unit tests pass.
• The fix matches the pattern used by accept_patient_reports and registration transitions, which already return true on success.