[automerge] Handling exception when per-use prompt cannot be generated 2p:...

[automerge] Handling exception when per-use prompt cannot be generated 2p: f41f0dea 2p: de7cecc6

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/17575366

Bug: 228037077
Change-Id: Ie6ccc2438dbb0a63aab1aa571521fd42f2f4a5fb