Add a content description to the app info button.

This resolves an issue where Talkback would call the
app info button "unlabelled."

Change-Id: I59d8639584c48d8eeb7640bdac3d18bc7667009f
Fixes: 35338852
Test: Settings Robotest

src/com/android/settings/applications/AppHeaderController.java

@@ -267,6 +267,8 @@ public class AppHeaderController {
                         || !AppHeader.includeAppInfo(mFragment)) {
                     button.setVisibility(View.GONE);
                 } else {
+                    button.setContentDescription(
+                            mContext.getString(R.string.application_info_label));
                     button.setImageResource(com.android.settings.R.drawable.ic_info);
                     button.setOnClickListener(v -> AppInfoBase.startAppInfoFragment(
                             InstalledAppDetails.class, R.string.application_info_label,