Fixes auto assigning forces to official challenge scenarios (#8612)

[VicenteCartas]

This fixes #8612

I couldn't repro manually, but the test will check that a force is not auto-assigned to an official challenge scenario. Without this change, this is the test result, where stratcon tries to auto-assign the foce:

With the change, this test passes correctly.

[Copilot]

Pull request overview

Adjusts StratCon force auto-assignment behavior so Official Challenge scenarios don’t forcibly pre-select/assign a player force, addressing #8612 in the StratCon scenario generation/deployment flow.

Changes:

• Prevent auto-assignment for Official Challenge scenarios when generating scenarios for existing forces.
• Prevent auto-assignment when deploying a force onto a hex that already contains an Official Challenge scenario.
• Add unit tests covering deployForceToCoords() behavior for challenge vs non-challenge scenarios.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
MekHQ/src/mekhq/campaign/stratCon/StratConRulesManager.java	Adds Official Challenge checks to bypass auto-assignment paths in scenario generation/deployment.
MekHQ/unittests/mekhq/campaign/stratCon/StratConRulesManagerTest.java	Adds regression tests asserting forces are not auto-assigned to Official Challenge scenarios (and still are for normal scenarios).

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[codecov]

Codecov Report

❌ Patch coverage is 41.66667% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 13.27%. Comparing base (6e9f6a0) to head (f23ffea).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
.../mekhq/campaign/stratCon/StratConRulesManager.java	50.00%	4 Missing and 1 partial ⚠️
.../src/mekhq/campaign/stratCon/StratConScenario.java	0.00%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #8811      +/-   ##
============================================
+ Coverage     13.22%   13.27%   +0.04%     
- Complexity     7874     7893      +19     
============================================
  Files          1306     1306              
  Lines        169191   169193       +2     
  Branches      25458    25460       +2     
============================================
+ Hits          22383    22459      +76     
+ Misses       144632   144535      -97     
- Partials       2176     2199      +23     

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