Fix TcpListener disposal in TcpClientNmeaStreamReaderTests

[Copilot]

TcpListener instances were created outside try blocks, meaning Stop() wouldn't be called if exceptions occurred during setup.

Changes

• Refactored all 11 test methods using TcpListener to ensure proper cleanup
• Listener is now declared as nullable and initialized inside the try block
• Finally block uses null-conditional listener?.Stop() for safe disposal

Before:

TcpListener listener = new(IPAddress.Loopback, 0);
listener.Start();
try { ... }
finally { listener.Stop(); }  // Never reached if Start() throws

After:

TcpListener? listener = null;
try {
    listener = new(IPAddress.Loopback, 0);
    listener.Start();
    ...
}
finally { listener?.Stop(); }  // Always safe

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[Copilot]

Pull request overview

This PR refactors 11 test methods in TcpClientNmeaStreamReaderTests to ensure proper cleanup of TcpListener resources, even when exceptions occur during test setup. The refactoring prevents potential resource leaks by guaranteeing that Stop() is safely called in all scenarios.

Key Changes:

• Moved TcpListener initialization from outside try blocks to inside them
• Changed listener declarations to nullable type (TcpListener?) initialized to null
• Updated finally blocks to use null-conditional operator (listener?.Stop()) for safe cleanup

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[Copilot]

Disposable 'TcpListener' is created but not disposed.

[Copilot]

Disposable 'TcpListener' is created but not disposed.

[Copilot]

Disposable 'TcpListener' is created but not disposed.

[Copilot]

Disposable 'TcpListener' is created but not disposed.

[Copilot]

Disposable 'TcpListener' is created but not disposed.

[Copilot]

Disposable 'TcpListener' is created but not disposed.

[Copilot]

Disposable 'TcpListener' is created but not disposed.

[Copilot]

Disposable 'TcpListener' is created but not disposed.

[Copilot]

Disposable 'TcpListener' is created but not disposed.

[Copilot]

Disposable 'TcpListener' is created but not disposed.