Add a dropdown button to choose between image providers

Author: YoussefLasheen

lib/view/pages/wallpaper/wallpaper_page.dart

@@ -107,14 +107,27 @@ class WallpaperPage extends StatelessWidget {
           //TODO: Add the title and copyright info
           YaruRow(
               enabled: true,
-              trailingWidget: const Text('Image of the day from Bing'),
+              leadingWidget: const Text('Image of the day from '),
+              trailingWidget: DropdownButton<ImageOfTheDayProvider>(
+                  value: model.imageOfTheDayProvider,
+                  onChanged: (value) => model.setUrlWallpaperProvider(value!),
+                  items: const [
+                    DropdownMenuItem(
+                      child: Text('Bing'),
+                      value: ImageOfTheDayProvider.bing,
+                    ),
+                    DropdownMenuItem(
+                      child: Text('Nasa'),
+                      value: ImageOfTheDayProvider.nasa,
+                    ),
+                  ]),
               actionWidget: SizedBox(
                 width: 40,
                 height: 40,
                 child: OutlinedButton(
                   style: OutlinedButton.styleFrom(
                       padding: const EdgeInsets.all(0)),
-                  onPressed: () async => await model.refreshBingWallpaper(),
+                  onPressed: () async => model.refreshUrlWallpaper(),
                   child: const Icon(YaruIcons.refresh),
                 ),
               )),