Optimizations make Excavations Even More Unfair

[KynaTiona]

Sometime pre-25 and now, the power cells in Excavations were changed to automatically remove themselves after some time had passed (or possibly distance from players, not sure). This seems like an obvious optimization that reduces the unsightly clutter littering many battlefields, but in practice it makes the mission mode dramatically more unbalanced. The mission mode already has an issue where it doesn't have to spawn a power carrier if it doesn't want you, leaving you hanging around for potentially minutes accomplishing nothing. Previously, this was less of an issue as the level progressed, as there started to be more and more excess power cells lying around from previous excavators that it was less likely to be incapable of finding one. Now, however, that balancing factor has been removed, making it frustrating from start to finish.