frameworks/opt/net/ims: remove deprecated Mockito usages am: d8128886c6

Original change: https://android-review.googlesource.com/c/platform/frameworks/opt/net/ims/+/3505992

Change-Id: I5f0ec618e7b4deeef2918e1e8569b842d31a3bc3
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>