Time zone, Region, UTC picker

- Extract most common view related codes into BaseTimeZoneAdapter
  and BaseTimeZonePicker. Subclass handles the text formatting and
  order.
- Search view is added compared to previous version of time
  zone picker
- SpannableUtil is added to preserve spannable when formatting
  String resource.
- Fix the bug using GMT+<arabic> as time zone id. b/73132985
- Fix Talkback treating flags on screens as a separate element

Bug: 72146259
Bug: 73132985
Bug: 73952488
Test: mm RunSettingsRoboTests
Change-Id: I42c6ac369199c09d11e7f5cc4707358fa4780fed