Split robot load into it's own plan

[DominicOram]

Fixes #490 and fixes #302

To test:

• Confirm tests still pass and cover the same code without any logical changes

[rtuck99]

can we please rename this so that it's test_robot_load_then_centre instead of test_wait_for...?

[rtuck99]

I'm not massively keen on the RobotLoadAndEnergyChange name, I keep wanting to find a robot_load_and_energy_change plan but there isn't one. I think if it's an important aspect of the plan, the plan ought to include the name, otherwise the plan and the parameter / composite names ought to line up.

[DominicOram]

You're right. Ideally they should be separate but it's hard to do that whilst we can't do parallel plans. I will make them consistent in saying they do energy changes.

[rtuck99]

Apart from naming comment, all looks good

[codecov]

Codecov Report

Attention: Patch coverage is 97.67442% with 3 lines in your changes missing coverage. Please review.

Project coverage is 78.01%. Comparing base (f050458) to head (6ab10ed).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #491      +/-   ##
==========================================
+ Coverage   77.90%   78.01%   +0.11%     
==========================================
  Files          89       91       +2     
  Lines        6711     6754      +43     
==========================================
+ Hits         5228     5269      +41     
- Misses       1483     1485       +2     

Components	Coverage Δ
i24 SSX	57.12% <ø> (ø)
hyperion	96.24% <97.67%> (-0.02%)	⬇️
other	94.79% <ø> (ø)