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