Improve multicopter sequential desaturation unit testing

[MaEtUgR]

Solved Problem

When working on limited airmode #22706 I found that:

• I was writing my own desaturation unit tests while independently some got added
  Control Allocation Sequential Desaturation unit tests #22612
• Dependencies of the desaturation unit tests got broken
  Maintenance: Fix sequential desaturation unit test dependency #24735
• Quite some desaturation test cases were lost when removing the old mixing
  purge old mixing system #20108
• I started looking into how to deal with the hexarotor with one failed motor case. Limited airmode could be very useful because on whatever side the failing motor is, if it's not reversible it will saturate the entire allocation and the vehicle gets unstable without (limited) airmode. To test the cases I also used SIH with SIH: add Hexacopter X #24835.

Solution

1. I added a hexarotor geometry to effectiveness generation test.
2. I took over my unit test only dependency fix from Maintenance: Fix sequential desaturation unit test dependency #24735 (FYI @Jaeyoung-Lim )
3. I cleaned up the use of the ActuatorVector alias to be defined and used consistently.
4. I overhauled the entire desaturation unit tests to:
   • Use the test fixture I came up with that allows for having one line per test case with comprehensive numbers
   • Include the tests I had come up with so far
   • Include the already existing tests but adapted to the fixture
   • Include the quadrotor X tests from the original mixer introduced in
     MC: Multirotor mixer rewrite & Airmode for Yaw #10962

Changelog Entry

Improve multicopter sequential desaturation unit testing

Test coverage

I went through these unit tests quite a bit also to check which ones need to be adjusted to support limited airmode. But on the current logic, they still all pass like before, no surprises there.

Context

This is a good intermediate step to allow for proper testing of limited airmode and hexarotor motor failures. But to support those features there's still remaining work to be done even though I already made quite some progress.

[MaEtUgR]

I rebased on main and addressed the comment. Any other feedback?