feat(siai): add simvar to check inserted pin for say intentions pushback system

[Revyn112]

Fixes #[issue_no]

Summary of Changes

This update introduces the SimVar for SayIntentions.AI Pushback System by linking the data to the bypass pin check. This ensures accurate and dynamic display of the "N/W STRG DISC" ECAM MEMO message, reflecting the current bypass pin status.

Screenshots (if necessary)

References

Here is a demo of the SayIntentions.AI Pushback Demo on the A339X: https://cdn.discordapp.com/attachments/1298376948644315229/1319081989906890812/A339_Pushback_Support.mp4?ex=6764aa55&is=676358d5&hm=803d420b55a0f0f0febc8ae5e1071f9e74d4fdde58ee7757e3881e8be97963ff&

Additional context

More information about SayIntentions.AI pushback system: https://www.sayintentions.ai/post/neural-ai-managed-pushback-and-jetways

Discord username (if different from GitHub):

Testing instructions

1. Check if MSFS / FBW (EFB) Pushback System provide ECAM Memo Message.
2. Check if GSX Pushback System provide ECAM Memo Message.
3. Check if SayIntentions.AI Pushback System is provide ECAM Memo Message (will need a subscription and use of experimental server)

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]

I would rather our code doesn't end up littered with interfacing code for a bunch of undocumented proprietary systems. Perhaps we would be better to provide a well-documented API from our side that these external tools can utilise.

This interfacing code certainly does not belong inside the actual systems implementations.