Fix TypeCache to throw on duplicate attributes when necessary

[Youssef1313]

Fixes #4333

[Youssef1313]

@copilot Please add an MSTest acceptance test for this scneario:

[TestClass]
public class TestClass1
{
    [TestMethod]
    [MyTestMethod]
    public void Test1()
    {
    }

    [TestMethod]
    public void Test2()
    {
    }
}

[TestClass]
[MyTestClass]
public class TestClass2
{
    [TestMethod]
    public void Test1()
    {
    }
}

public class MyTestMethodAttribute : TestMethodAttribute
{
    public MyTestMethodAttribute([CallerFilePath] string callerFilePath = "", [CallerLineNumber] int callerLineNumber = -1)
        : base(callerFilePath, callerLineNumber)
    {
    }
}

public class MyTestClass : TestClassAttribute
{
}

[Copilot]

@Youssef1313 I've opened a new pull request, #7224, to work on those changes. Once the pull request is ready, I'll request review from you.