fix(efcs): fix ground spoiler thrust lever idle condition threshold

[lukecologne]

Fixes #8618

Summary of Changes

Changes ground spoiler logic, more specifically raises the thrust lever angle condition from <=0° to <20°, as per references.

Screenshots (if necessary)

References

Additional context

Discord username (if different from GitHub):

Testing instructions

Check that the ground spoilers work as intended, during RTO, goaround and landing

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 or flybywire-aircraft-a380-842 download link at the bottom of the page

[2hwk]

QA Report

Tier of Testing : 1 Date : 20/04/2024

Testing Process: Check that the ground spoilers work as intended, during RTO, goaround and landing

• [x] RTO
• [x] Go Around
• [x] Landing
• [x] Ground spoilers disarm correctly after landing
• [x] Spoiler behavior not on ground has not regressed

Negatives: N/A

Testing Results: Passed

Conclusions: Passed