Don't disable autobrightness with key press

- don't disable autobrightness on brightness up/down key press
- there are no other side effects to this
- the brightness changes are still considered as user interactions

Bug: 332323629
Flag: EXEMPT bug fix
Test: manual, atest DisplayServiceTests
Change-Id: Ia24f41b2eb2343b13000f1a28e3a75a497f5f354