Provides TC ID for accessibility framework feature for "about" and "learn more" part

Goal: Improve readability which is a bit difficult because of string concatenation for accurate translation.
Root cause: In some locales, framework features name would be a word rather than a product name. Hence it need to be in the different position in a sentence.
Solution: Use whole sentence to translate instead of concatenating the string could solve this issue.

Bug: 185478543
Test: make RunSettingsRoboTests ROBOTEST_FILTER=AccessibilityFooterPreferenceControllerTest
Change-Id: Id198805329be9c773df87f38a074ae956e4d0cdb

src/com/android/settings/accessibility/CaptionFooterPreferenceController.java

@@ -30,12 +30,18 @@ public class CaptionFooterPreferenceController extends AccessibilityFooterPrefer
     }
 
     @Override
-    protected String getLabelName() {
-        return mContext.getString(R.string.accessibility_captioning_title);
+    protected String getLearnMoreContentDescription() {
+        return mContext.getString(
+            R.string.accessibility_captioning_footer_learn_more_content_description);
     }
 
     @Override
-    protected int getHelpResource()  {
+    protected String getIntroductionTitle() {
+        return mContext.getString(R.string.accessibility_captioning_about_title);
+    }
+
+    @Override
+    protected int getHelpResource() {
         return R.string.help_url_caption;
     }
 }