Tweak rechargers icon handling so they don't update every process

[Vi3trice]

What Does This PR Do

Adds a check for a state change so it only updates the icon in process when it's appropriate. An early return is also added since it doesn't need to try to process further if there's nothing inserted into the recharger.

Why It's Good For The Game

Calling update_icon on every process isn't a good idea.

Testing

Used a recharger in its various states. Nothing changed visually, this is just so it doesn't go overboard with procs.

Changelog

N/A