fix: plutonium batteries no longer fully recharge if dropped before first charge cycle

[boniondev]

Purpose of change (The Why)

Followup/Fix for an exploit caused by #8342
Professions that spawn with a plutonium battery and drop it before the first charge cycle causes it to fully charge.

Describe the solution (The How)

This adds an item variable that is set to true when the player has it in their inventory. Even if the battery later gets dropped, it will "remember" it has been in a player inventory, and not fully charge, fixing the exploit. Contrary to what I thought, process_recharge_entry is actually called every tick, it just stops after the once_every check. This can thus be achieved without touching item.cpp.

Describe alternatives you've considered

Ideally you'd want to set the item var only once, but we currently do not have hooks/callbacks for when an item is picked up (do we?) (or if spawning with it would even trigger it)

Testing

• Spawn plutonium battery inside the inventory
• Discharge it a bit
• Drop it before 12 minutes have passed
• Wait 12 minutes
• Notice the battery does not fully charge, instead charging normally

Additional context

If there is some sort of callback or signal I can use, I'd be glad to use it. I'm not particularly happy with this implementation either.

Checklist

Mandatory

• I wrote the PR title in conventional commit format.
• I ran the code formatter.
• I linked any relevant issues using github keyword syntax like closes #1234 in Summary of the PR so it can be closed automatically. No issues have been opened regarding this exploit since it's so new
• I've committed my changes to new branch that isn't main so it won't cause conflict when updating main branch later.