Fix double refunding of organelle upgrade MP

[0HyperCube]

Brief Description of What This PR Does

When changing the organelle upgrade repeatedly in the same editor cycle, MP would be refunded twice (as detailed in #5524). This is because the cost of an upgrade also includes the negated cost of the current upgrade, meanwhile the editor refunds MP where ActionInterferenceMode.Combinable is returned as the interference mode.

Related Issues
Closes #5524

Progress Checklist

Note: before starting this checklist the PR should be marked as non-draft.

• PR author has checked that this PR works as intended and doesn't
  break existing features:
  https://wiki.revolutionarygamesstudio.com/wiki/Testing_Checklist
  (this is important as to not waste the time of Thrive team
  members reviewing this PR)
• Initial code review passed (this and further items should not be checked by the PR author)
• Functionality is confirmed working by another person (see above checklist link)
• Final code review is passed and code conforms to the
  styleguide.

Before merging all CI jobs should finish on this PR without errors, if
there are automatically detected style issues they should be fixed by
the PR author. Merging must follow our
styleguide.

[revolutionary-bot]

The lead programmer for Thrive is currently on vacation until 2025-01-07. Until then other programmers will try to make pull request reviews, but please be patient if your PR is not getting reviewed.

PRs may be merged after multiple programmers have approved the changes (especially making sure to ensure style guide conformance and gameplay testing are good). If there are no active experienced programmers who can perform merges, PRs may need to wait until the lead programmer is back to be merged.

[dligr]

This PR fixes the issue based on my testing; the solution makes sense to me too.