Fix LT-22295: Don't crash if MakeDefaultSelection is called early

[jasonleenaylor]

This change is 

[Copilot]

Pull Request Overview

Fixes a crash in the FocusBoxController when MakeDefaultSelection is called before InterlinWordControl is initialized. The fix adds null checking and defers the operation to the idle queue if the control is not ready yet.

• Added null checking for InterlinWordControl before calling MakeDefaultSelection
• Implemented deferred execution using the idle queue when the control is not yet available
• Used null-conditional operator for safety in the deferred callback

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[Copilot]

The lambda function always returns true regardless of whether MakeDefaultSelection() was actually called. Consider returning a meaningful value that indicates whether the operation was successful, or add error handling if the InterlinWordControl is still null when the deferred operation executes.

Suggested change

	InterlinWordControl?.MakeDefaultSelection();
	return true;
	if (InterlinWordControl != null)
	{
	InterlinWordControl.MakeDefaultSelection();
	return true;
	}
	else
	{
	// Optionally log or handle the error here.
	// System.Diagnostics.Debug.WriteLine("InterlinWordControl is still null in deferred MakeDefaultSelection.");
	return false;
	}

[mark-sil]

@mark-sil reviewed 1 of 1 files at r1, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @jasonleenaylor)

[mark-sil]

Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @jasonleenaylor)