Fix double search icon in wifi calling page

- Moved fragments into wifi sub-package.
- Cleaned up inheritance for WifiCallingSettings
- Attach help and search action menu controller correctly.

Change-Id: I0bc8ab99df5d8c5ea64fb64de5ae70c2c9bd6f31
Fixes: 72958674
Test: robotest

tests/robotests/src/com/android/settings/suggestions/SettingsSuggestionsTest.java

@@ -68,7 +68,7 @@ public class SettingsSuggestionsTest {
 
     @Test
     public void wifiCallingSuggestion_isValid() {
-        assertSuggestionEquals("com.android.settings.wifi.WifiCallingSuggestionActivity",
+        assertSuggestionEquals("com.android.settings.wifi.calling.WifiCallingSuggestionActivity",
                 CATEGORY_FIRST_IMPRESSION,
                 R.string.wifi_calling_suggestion_title, R.string.wifi_calling_suggestion_summary);
     }