Reduce boxing in logging (#88560)

- Logging got overhauled to use CompositeFormat in .NET 8, this allows for non boxing string formatting via string.Format. There's one piece of code that boxing the generic argument before handing off to string.Format so remove it for primitive types and enums.

Author: davidfowl

src/libraries/Microsoft.Extensions.Logging.Abstractions/src/LogValuesFormatter.cs

@@ -263,8 +263,15 @@ private static object FormatArgument(object? value)
             return TryFormatArgumentIfNullOrEnumerable(value, ref stringValue) ? stringValue : value!;
         }
 
-        private static bool TryFormatArgumentIfNullOrEnumerable(object? value, [NotNullWhen(true)] ref object? stringValue)
+        private static bool TryFormatArgumentIfNullOrEnumerable<T>(T? value, [NotNullWhen(true)] ref object? stringValue)
         {
+            // Avoiding boxing of known types
+            if (typeof(T).IsPrimitive || typeof(T).IsEnum)
+            {
+                stringValue = null;
+                return false;
+            }
+
             if (value == null)
             {
                 stringValue = NullValue;