fix(a380x): Pressurization & AMU SimVar fixes

[flogross89]

Summary of Changes

Two fixes for SimVars, gets rid of error messages in MSFS2024. Won't have a huge functional impact I guess though.

Out of scope: L:A32NX_PRESS_OUTFLOW_VALVE_x_OPEN_PERCENTAGE_ANIM won't be populated, i.e. #9578 needs to be fixed with another PR

Screenshots (if necessary)

References

Additional context

Discord username (if different from GitHub):

Testing instructions

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.

1. Make sure you are signed in to GitHub
2. Click on the Checks tab on the PR
3. On the left side, find and click on the PR Build tab
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

[tracernz]

Can you please split these into PRs that do one thing when you are ready to submit them? It's better for git blame, and also a lot better if one needs reverted (and also see https://github.com/flybywiresim/aircraft/blob/master/.github/Contributing.md).
If it's anything like the A32NX work I already did, you will find a lot of them are also bugs on FS2020, just less noticeable.

[flogross89]

Can you please split these into PRs that do one thing when you are ready to submit them? It's better for git blame, and also a lot better if one needs reverted (and also see https://github.com/flybywiresim/aircraft/blob/master/.github/Contributing.md). If it's anything like the A32NX work I already did, you will find a lot of them are also bugs on FS2020, just less noticeable.

The fixes until now seem to be without QA, so I can do that