Closes #96430

Just to be clear the issue title starts with InputBox which might mean the generic InputBox although that's not directly used in showInputBox, quickinput's InputBox (ui.inputBox) along with a message dom node (ui.message) exclusive to quickinput is used instead. So this PR adds support of codicons for quick input's prompt and not for generic InputBox.

I think it's worth mentioning that quickinput should (afaict) use generic InputBox's message for prompt which would also solve #82112, because the generic already supports rich text message. I might look into fixing this as well.

How to test:

1. Make a temporary extension and execute

vscode.window.showInputBox({
	// using bigger prompt to check alignment when text gets wrapped into lines as well
	prompt: "$(add) Lorem ipsum, dolor sit amet consectetur adipisicing elit. Magni odio $(wrench) quisquam illo ea nobis provident laborum nam nostrum voluptatibus ullam ratione, eligendi rerum."
});

2. Check if you see the codicons.
3. Check if they're properly aligned.