Diff controls alignment fix

What does this MR do and why?

This MR fixes a slight vertical misalignment in the diff controls.

Note that we don't seem to be able to use baseline as this would shift everything down so it's not centered anymore.

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

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How to set up and validate locally

1. Go to a MR (e.g. http://gdk.test:3000/flightjs/Flight/-/merge_requests/4)
2. Go to Changes tab

Related to #430246 (closed)