Fix attribute order dependency in ModelAttributesTest

[medhatiwari]

This PR fixes a test failure on Mono runtime by removing dependency on attribute ordering in ModelAttributesTest.GetAttributesForParameter_SomeAttributes

Description

The test was failing on Mono runtime because it assumed SerializableAttribute would be the first attribute returned by GetCustomAttributes()

Failed Microsoft.AspNetCore.Mvc.ModelBinding.ModelAttributesTest.GetAttributesForParameter_SomeAttributes
Error: Assert.IsType() Failure: Value is not the exact type
Expected: typeof(System.SerializableAttribute) 
Actual:   typeof(System.Runtime.CompilerServices.IsReadOnlyAttribute)

see detail here

As pointed out by @jkotas in dotnet/runtime#117864:

"The order of attributes is not significant. [...] If the test depends on attributes being returned in a specific order, it should be fixed to not do that."

The C# Specification confirms that attribute order is not guaranteed

This change ensures the test verifies the presence of the expected attribute without depending on its position, making it compliant with the C# specification and compatible across all .NET runtimes.

cc: @jkotas

[Copilot]

Pull Request Overview

This PR fixes a test failure on Mono runtime by removing the dependency on attribute ordering in ModelAttributesTest.GetAttributesForParameter_SomeAttributes. The test was failing because it assumed SerializableAttribute would always be the first attribute returned by GetCustomAttributes(), but attribute order is not guaranteed by the C# specification.

Key Changes

• Replaced order-dependent Assert.Collection with order-agnostic Assert.Contains check
• Updated test to verify presence of SerializableAttribute without assuming its position
• Added explanatory comment about the order-agnostic nature of the check

[jkotas]

LGTM!