Change default long-press time to 400ms

The default long-press time has been changed from 500ms to 400ms by
b/30159825. so the values for the list of long-press timeout options
in Settings app should be changed.

Bug: 35226519
Test: manual - go to Settings > Accessibility > Touch & hold delay

Change-Id: I8e2421ea4119742bb6bf0e27688c65e3de3099dc