Only Left and returnValue gets checked for dynamic in signature (#69214)

In CSharpcompilation there was a signature check for dynamic Types but only left and return were checked

src/Compilers/CSharp/Portable/Compilation/CSharpCompilation.cs

@@ -4127,7 +4127,7 @@ void validateSignature()
                 // Dynamic built-in operators allow virtually all operations with all types.  So we do no further checking here.
                 if (csharpReturnType.TypeKind is TypeKind.Dynamic ||
                     csharpLeftType.TypeKind is TypeKind.Dynamic ||
-                    csharpReturnType.TypeKind is TypeKind.Dynamic)
+                    csharpRightType.TypeKind is TypeKind.Dynamic)
                 {
                     return;
                 }