feat(a32nx): approach via differentiation and layout fix

[tracernz]

Fixes #[issue_no]

Summary of Changes

• Add approach via differentiation per H4 changes.
• Remove INSERT/ERASE prompts for TMPY on APPROACH VIAS page as on the real thing.
• Swap the up/down arrows which were always wrong.

Screenshots (if necessary)

References

On request.

Additional context

Discord username (if different from GitHub):

Testing instructions

Select a variety of approaches at different airports with a without STARs selected and ensure the VIAS page shows all of the transitions, with those connecting to the selected STAR show as "available" and those not as "other appr vias".

How to download the PR for QA

Every new commit to this PR will cause new A32NX and A380X artifacts to be created, built, and uploaded.

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4. Click on either flybywire-aircraft-a320-neo, flybywire-aircraft-a380-842 (4K) or flybywire-aircraft-a380-842 (8K) download link at the bottom of the page