Update BasemapGallery and BasemapGalleryItem classes

- In `BasemapGallery.Appearance.cs`, the visibility of `PART_LoadingScrim` Grid has been set to `False`.
- The `LoadBasemaps` method in `BasemapGallery.cs` and `BasemapGallery.Windows.cs` has been removed and its functionality has been moved to the `BasemapGallery_Loaded` method.
- In `BasemapGalleryItem.cs`, the `Equals` method has been updated to check for equality of `BaseLayers` count and existence of all layers in `Basemap` in the `other` object, in addition to the existing checks.

src/Toolkit/Toolkit.Maui/BasemapGallery/BasemapGallery.Appearance.cs

@@ -173,7 +173,7 @@ static BasemapGallery()
                                                     </Style>
                                                 </Grid.Resources>
                                         <CollectionView x:Name=""PART_InnerListView"" HorizontalOptions=""Fill"" VerticalOptions=""Fill"" SelectionMode=""Single"" BackgroundColor=""{{AppThemeBinding Light=#fff,Dark=#353535}}"" />
-                                        <Grid x:Name=""PART_LoadingScrim"">
+                                        <Grid x:Name=""PART_LoadingScrim"" IsVisible=""False"">
                                             <Grid BackgroundColor=""{{AppThemeBinding Light=White, Dark=Black}}"" Opacity=""0.3"" />
                                             <ActivityIndicator IsRunning=""True"" HorizontalOptions=""Center"" VerticalOptions=""Center"" />
                                         </Grid>

src/Toolkit/Toolkit.Maui/BasemapGallery/BasemapGallery.cs

@@ -46,21 +46,10 @@ public BasemapGallery()
 
     private void BasemapGallery_Loaded(object? sender, EventArgs e)
     {
-        LoadBasemaps();
-    }
-
-    private void LoadBasemaps()
-    {
-        _controller.IsLoading = true;
-        if (AvailableBasemaps == null)
+        if (AvailableBasemaps is null)
         {
             _ = _controller.LoadFromDefaultPortal();
         }
-        else
-        {
-            _controller.AvailableBasemaps = AvailableBasemaps;
-        }
-        _controller.IsLoading = false;
     }
 
     private void HandleControllerPropertyChanged(object? sender, PropertyChangedEventArgs e)

src/Toolkit/Toolkit.UI.Controls/BasemapGallery/BasemapGallery.Windows.cs

@@ -50,21 +50,10 @@ public BasemapGallery()
 
         private void BasemapGallery_Loaded(object? sender, RoutedEventArgs e)
         {
-            LoadBasemaps();
-        }
-
-        private void LoadBasemaps()
-        {
-            _controller.IsLoading = true;
-            if (AvailableBasemaps == null)
+            if (AvailableBasemaps is null)
             {
                 _ = _controller.LoadFromDefaultPortal();
             }
-            else
-            {
-                _controller.AvailableBasemaps = AvailableBasemaps;
-            }
-            _controller.IsLoading = false;
         }
 
         private void HandleControllerPropertyChanged(object? sender, PropertyChangedEventArgs e)

src/Toolkit/Toolkit/UI/Controls/BasemapGallery/BasemapGalleryItem.cs

@@ -246,7 +246,8 @@ internal bool EqualsBasemap(Basemap? other)
                 return false;
             }
 
-            return other == Basemap || other.Name == Basemap?.Name
+            return other == Basemap || (Basemap.BaseLayers.Count == other.BaseLayers.Count
+                                        && Basemap.BaseLayers.All(layer => other?.BaseLayers.FirstOrDefault(l => l.Name == layer.Name) is not null))
                                     || (other.Item?.ItemId != null && other.Item?.ItemId == Basemap?.Item?.ItemId)
                                     || (other.Uri != null && other.Uri == Basemap?.Uri);
         }