Address review comments

Co-authored-by: Bond-009 <bond.009@outlook.com>

MediaBrowser.Providers/Manager/MetadataService.cs

@@ -1071,10 +1071,14 @@ namespace MediaBrowser.Providers.Manager
                 var key = id.Key;
 
                 // Don't replace existing Id's.
-                if (replaceData || !target.ProviderIds.ContainsKey(key))
+                if (replaceData)
                 {
                     target.ProviderIds[key] = id.Value;
                 }
+                else
+                {
+                    target.ProviderIds.TryAdd(key, id.Value);
+                }
             }
 
             MergeAlbumArtist(source, target, replaceData);
@@ -1120,10 +1124,7 @@ namespace MediaBrowser.Providers.Manager
                 {
                     foreach (var providerId in personInSource.ProviderIds)
                     {
-                        if (!person.ProviderIds.ContainsKey(providerId.Key))
-                        {
-                            person.ProviderIds[providerId.Key] = providerId.Value;
-                        }
+                        person.ProviderIds.TryAdd(providerId.Key, providerId.Value);
                     }
 
                     if (string.IsNullOrWhiteSpace(person.ImageUrl))

tests/Jellyfin.Providers.Tests/Manager/ItemImageProviderTests.cs

@@ -157,8 +157,9 @@ namespace Jellyfin.Providers.Tests.Manager
             {
                 Assert.True(changed);
                 // before and after paths are the same, verify updated by size reset to 0
-                Assert.Equal(imageCount, item.GetImages(imageType).Count());
-                foreach (var image in item.GetImages(imageType))
+                var typedImages = item.GetImages(imageType).ToArray();
+                Assert.Equal(imageCount, typedImages.Length);
+                foreach (var image in typedImages)
                 {
                     Assert.Equal(updatedTime, image.DateModified);
                     Assert.Equal(0, image.Height);