[automerger skipped] Add API for MockModemService overriding mechanism am:...

[automerger skipped] Add API for MockModemService overriding mechanism am: 3b1b77ec am: ffc36dc0 am: 3cf94814 am: 93c2db8a -s ours

am skip reason: Merged-In Id27d89c23d1fef4c1848c091183991384e8871c1 with SHA-1 73b7b287 is already in history

Original change: https://android-review.googlesource.com/c/platform/frameworks/opt/telephony/+/1927020

Change-Id: Ic3e3c972f30be0963216d0cf726979631a6a5abd