Fix UX problems in time zone pickers

- Remove emoji region flag in the region picker.
  It's more consistent with locale picker which shows no flag in region
  picker
- Remove redundant information in the summary field
  e.g. same GMT offset in primary and secondary field in fixed offset
  picker
- Better mode switching flow. Switch region/fixed offset mode
only when the user confirms their selection in the picker.

Bug: 73952488
Test: m RunSettingsRoboTests ROBOTEST_FILTER=com.android.settings.datetime.timezone
Change-Id: Id5da8a2516acd10c9a3d71181e94bc617d797d20

src/com/android/settings/datetime/timezone/BaseTimeZoneInfoPicker.java

@@ -31,6 +31,7 @@ import java.util.ArrayList;
 import java.util.Date;
 import java.util.List;
 import java.util.Locale;
+import java.util.Objects;
 
 /**
  * Render a list of {@class TimeZoneInfo} into the list view in {@class BaseTimeZonePicker}
@@ -135,8 +136,11 @@ public abstract class BaseTimeZoneInfoPicker extends BaseTimeZonePicker {
                     name = mTimeZoneInfo.getStandardName();
                 }
             }
-            if (name == null) {
-                return mTimeZoneInfo.getGmtOffset();
+
+            // Ignore name / GMT offset if the title shows the same information
+            if (name == null || name.equals(mTitle)) {
+                CharSequence gmtOffset = mTimeZoneInfo.getGmtOffset();
+                return gmtOffset == null || gmtOffset.toString().equals(mTitle) ? "" : gmtOffset;
             } else {
                 return SpannableUtil.getResourcesText(mResources,
                         R.string.zone_info_offset_and_name, mTimeZoneInfo.getGmtOffset(), name);