Migrate search bar style preferences

preferences/src/main/java/de/mm20/launcher2/preferences/Defaults.kt

@@ -101,5 +101,10 @@ fun createFactorySettings(context: Context): Settings {
                 .setColumnCount(context.resources.getInteger(R.integer.config_columnCount))
                 .build()
         )
+        .setSearchBar(
+            Settings.SearchBarSettings.newBuilder()
+                .setSearchBarStyle(Settings.SearchBarSettings.SearchBarStyle.Transparent)
+                .build()
+        )
         .build()
 }

preferences/src/main/proto/settings.proto

@@ -123,4 +123,14 @@ message Settings {
   }
   GridSettings grid = 19;
 
+  message SearchBarSettings {
+    enum SearchBarStyle {
+      Transparent = 0;
+      Solid = 1;
+      Hidden = 2;
+    }
+    SearchBarStyle search_bar_style = 1;
+  }
+  SearchBarSettings search_bar = 20;
+
 }