Mark non actionable preferences as non-selectable

Test: navigate the conversations page with switch access enabled
Fixes: 178765656
Change-Id: If5d5dd301e2d95b4aa7512f58a6e1adf01f3dbf0

res/xml/conversation_list_settings.xml

@@ -34,6 +34,7 @@
         settings:allowDividerBelow="true" >
         <Preference
             android:key="behavior"
+            android:selectable="false"
             android:summary="@string/important_conversation_behavior_summary"/>
         <!-- Important conversations added here -->
         <PreferenceCategory

src/com/android/settings/notification/app/AllConversationsPreferenceController.java

@@ -55,6 +55,7 @@ public class AllConversationsPreferenceController extends ConversationListPrefer
         Preference pref = new Preference(mContext);
         pref.setOrder(1);
         pref.setSummary(R.string.other_conversations_summary);
+        pref.setSelectable(false);
         return pref;
     }