Tweak princess gravity PSR handling

[Sleet01]

This increases Princess's caution when moving on maps with high or low gravity:

• On low-gravity ground maps, ground units will recognize the PSR danger of exceeding their normal Run / Flank / Jump MP
• On high-gravity ground maps, ground units will recognize the PSR danger of using jump MPs, but Run / Flank will not be penalized.

Also reverted an inadvertent change to the Low/High-G nag checks that I did during the bog-down work.
Additionally, reverts MoveStep.java to space-based indentation.

Testing:

• Ran 12 v 12 bot matches with VTOL, hover, ground tank, and fast Light 'mechs (with and without jumping) to compare low- and high-gravity performance across various G levels.
• Ran all 3 projects' unit tests.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 28.98%. Comparing base (cab504f) to head (8bab678).
Report is 134 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #5864      +/-   ##
============================================
- Coverage     28.98%   28.98%   -0.01%     
- Complexity    13909    13913       +4     
============================================
  Files          2512     2512              
  Lines        267229   267321      +92     
  Branches      47780    47806      +26     
============================================
+ Hits          77462    77473      +11     
- Misses       185817   185894      +77     
- Partials       3950     3954       +4     

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