Fix Out of Bounds read in TextDescriptions.cpp am: b63d4e785b am: a18815ba8d

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/av/+/18993507

Change-Id: I0ffcaccbef809d71f4b4c7e32e2c4f640844c9f2
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>