Fix TUnit0023 false positive for Func<IDisposable> fields

[Copilot]

TUnit0023 incorrectly warns that Func<IDisposable> fields should be disposed, but delegate types are not disposable—only the objects they create are.

public class ExampleTest
{
    private readonly Func<IMyInterface> _factory;

    public ExampleTest()
    {
        _factory = () => new MyClass(); // False positive: TUnit0023 warning
    }

    [Test]
    public void Test1()
    {
        using var t = _factory(); // Result is properly disposed here
    }
}

Changes

• DisposableFieldPropertyAnalyzer.cs: CheckSetUps now verifies the field/property type is disposable before flagging, matching the existing logic in CheckFieldInitializers
• DisposableFieldPropertyAnalyzerTests.cs: Added test coverage for Func<T> assignments in constructors and Before hooks

Original prompt

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This section details on the original issue you should resolve

<issue_title>[Bug]: Compiler warning TUnit0023 for variable that cannot be disposed</issue_title>
<issue_description>### Description

The warning TUnit0023 is given for a member variable of type Func<IDisposable>, but the member variable itself cannot be disposed of.

Expected Behavior

I would not expect a compiler warning.

Actual Behavior

Compiling the below code results in the warning error TUnit0023: _factory should be disposed within a clean up method.

Steps to Reproduce

Compile the following code in a TUnit project:

public interface IMyInterface : IDisposable
{
}

public class MyClass : IMyInterface
{
    public void Dispose()
    {
        Console.WriteLine("disposed");
    }
}

public class ExampleTest
{
    private readonly Func<IMyInterface> _factory = () => new MyClass();

    [Test]
    public async Task Test1()
    {
        using var t = _factory();
    }
}

TUnit Version

1.9.2

.NET Version

.NET 10

Operating System

Windows

IDE / Test Runner

dotnet CLI (dotnet test / dotnet run)

Error Output / Stack Trace

error TUnit0023: _factory should be disposed within a clean up method

Additional Context

IDE-Specific Issue?

• I've confirmed this issue occurs when running via dotnet test or dotnet run, not just in my IDE</issue_description>

<agent_instructions>Read the latest comment in addition to the description for full context</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes [Bug]: Compiler warning TUnit0023 for variable that cannot be disposed #4243

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