Disable key repeat when it is switched off

Read whether key repeats are disabled via settings and disable
generation of key repeats if so.

Bug: 336585002
Test: atest InputDispatcherKeyRepeatTest
Test: atest InputManagerServiceTests
Flag: com.android.input.flags.keyboard_repeat_keys
Change-Id: I871bbfc0808bde4a6f85b7ea47ea92d4e80156c7