[Bug]: Repairing a damaged ACU with sparkies after assisting an upgrade incorrectly uses the upgrade's resource drain

### Describe the Bug

Assisting an idle damaged ACU with sparkies will repair the ACU at a low cost. However, if they finish assisting the ACU on an upgrade and continue assisting to repair it, the repairs will be at the same cost the upgrade was using.

### Reproduce the bug

Step 1. Spawn some pgens and mexes
Step 2. Damage your ACU in sandbox with ctrl k of energy storages
Step 3. Start upgrade and assist it with sparkies
Step 4. Upgrade finishes, Resource drain of repair is equal to resource drain of upgrade
https://replay.faforever.com/26314284

### Screenshots

_No response_

### Additional context

Bugged when using sparkies, fine when using T2 engineers. The difference is that T2 engineers pause assistance for a tiny bit before assisting the ACU again for repairs, with adjusted resource drain. Sparkies however keep assisting without that pause, still draining the same amount of resources as during the upgrade.