The PK settings UI should show subtype labels instead of the subtype's language names.

1. Use InputMethodSubtype#getDisplayName()
2. Sorting by label

Video: https://screencast.googleplex.com/cast/NjEzMjM3OTI0OTgwMzI2NHxiODBhNjQzZi1kZA

Bug: 271504879
Test: manual
Change-Id: Ia2be6f3a007c678e62bdda21fe20d95a2b304d70

src/com/android/settings/inputmethod/NewKeyboardSettingsUtils.java

@@ -72,24 +72,28 @@ public class NewKeyboardSettingsUtils {
     }
 
     static class KeyboardInfo {
-        String mLanguage;
+        CharSequence mSubtypeLabel;
         String mLayout;
         InputMethodInfo mInputMethodInfo;
         InputMethodSubtype mInputMethodSubtype;
 
         KeyboardInfo(
-                String language,
+                CharSequence subtypeLabel,
                 String layout,
                 InputMethodInfo inputMethodInfo,
                 InputMethodSubtype inputMethodSubtype) {
-            mLanguage = language;
+            mSubtypeLabel = subtypeLabel;
             mLayout = layout;
             mInputMethodInfo = inputMethodInfo;
             mInputMethodSubtype = inputMethodSubtype;
         }
 
-        String getLanguage() {
-            return mLanguage;
+        String getPrefId() {
+            return mInputMethodInfo.getId() + "_" + mInputMethodSubtype.hashCode();
+        }
+
+        CharSequence getSubtypeLabel() {
+            return mSubtypeLabel;
         }
 
         String getLayout() {