[fix] exclude NETFRAMEWORK from DisposeAsync override in FileTests

Author: i4004

src/Simplify.Web.Tests/Responses/FileTests.cs

@@ -115,7 +115,7 @@ protected override void Dispose(bool disposing)
 			base.Dispose(disposing);
 		}
 
-#if !NETSTANDARD2_0
+#if !(NETSTANDARD2_0 || NETFRAMEWORK)
 		public override async ValueTask DisposeAsync()
 		{
 			Disposed = true;