Add search index into WallpaperSuggestionActivity

.Use the Indexable interface for WallpaperSuggestionActivity and implement the getRawDataToIndex
.Remove the search index in the WallpaperTypeSettings
.Add full class name of the WallpaperTypeSettings into grandfather_not_implementing_index_provider

Bug: 63117104
Test: robotest & Manual View
Change-Id: I73f43e4996efbe857d74df297ea0d08eb1b640ac
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index 9f6cdb5..c83c14d 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -795,7 +795,8 @@
 
         <activity android:name="Settings$WallpaperSettingsActivity"
                   android:label="@string/wallpaper_settings_fragment_title"
-                  android:icon="@drawable/ic_wallpaper">
+                  android:icon="@drawable/ic_wallpaper"
+                  android:exported="true">
             <meta-data android:name="com.android.settings.FRAGMENT_CLASS"
                        android:value="com.android.settings.wallpaper.WallpaperTypeSettings" />
         </activity>