perf: Additional changes to mitigate PG-AOT dotnet/runtime issue #56309

See unoplatform#7005 for additional details

Author: jeromelaban

src/Uno.UI/UI/Xaml/ResourceResolver.cs

@@ -210,8 +210,14 @@ internal static bool ApplyVisualStateSetter(SpecializedResourceDictionary.Resour
 		/// </summary>
 		private static bool TryStaticRetrieval(in SpecializedResourceDictionary.ResourceKey resourceKey, object context, out object value)
 		{
-			foreach (var source in CurrentScope.Sources)
+			// This block is a manual enumeration to avoid the foreach pattern
+			// See https://github.com/dotnet/runtime/issues/56309 for details
+			var sourcesEnumerator = CurrentScope.Sources.GetEnumerator();
+
+			while(sourcesEnumerator.MoveNext())
 			{
+				var source = sourcesEnumerator.Current;
+
 				var dictionary = (source.Target as FrameworkElement)?.Resources
 					?? source.Target as ResourceDictionary;
 				if (dictionary != null && dictionary.TryGetValue(resourceKey, out value, shouldCheckSystem: false))

src/Uno.UI/UI/Xaml/Style/Style.cs

@@ -67,9 +67,13 @@ internal void ApplyTo(DependencyObject o, DependencyPropertyValuePrecedences pre
 #endif
 			{
 				ResourceResolver.PushNewScope(_xamlScope);
-				foreach (var pair in flattenedSetters)
+
+				// This block is a manual enumeration to avoid the foreach pattern
+				// See https://github.com/dotnet/runtime/issues/56309 for details
+				var settersEnumerator = flattenedSetters.GetEnumerator();
+				while (settersEnumerator.MoveNext())
 				{
-					pair.Value(o);
+					settersEnumerator.Current.Value(o);
 				}
 
 				// Check tree for resource binding values, since some Setters may have set ThemeResource-backed values