Adjust A11y Shortcut settings to use lowercase shortcut names.

Per go/android-naming these strings should be lowercase when
used in the middle of a sentence because they are generic
descriptive names and not branded names.

Bug: none
Change-Id: I0508a5cbdba20a1bd2d6db66e0e7183845e503ad
Test: build & install & check string
Flag: EXEMPT low risk bugfix