Merge "Fix NPE in TTS service if no engine string" into udc-qpr-dev am: a3f36b1e6f am: 88696daae3

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/24758913

Change-Id: Ia83e69ffa51dfb86ee23cf8de87d7de4ade2a6ce
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>