Merge "Fix NPE in TTS service if no engine string" into udc-dev am: 987b2e7d35 am: 2b4d5f1673

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/24758914

Change-Id: I96df36cf6abc360ad67f117dab6cfe1d820f272d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>