Historically, we've been passing in all MessageBox parameters individually, which makes augmenting or improving MessageBox functionality challenging because to change or add even one argument requires a huge cascade of argument changes that leaves room for errors.
For other file dialog related APIs, we use a struct (DialogSettings), and so this PR takes a similar approach and refactors MessageBox parameters into a struct (MessageBoxSettings) which we then use to simplify argument passing and which will enable us to more quickly iterate and improve upon functionality in the future.
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