Rename handover failure constant per API review comments.

Expanding EMERG to EMERGENCY.

Test: Build code
Bug: 74831393
Merged-In: Ic0555b20dc508d022c0165a5d9dc3b40b33db70e
Change-Id: Ic0555b20dc508d022c0165a5d9dc3b40b33db70e
(cherry picked from commit a4ef504b)