NPCs try not to throw their weapons

[RenechCDDA]

Summary

Bugfixes "NPCs won't throw their last, best weapon"

Purpose of change

NPCs still trying to throw good melee weapons in some circumstances...

• Fixes #71526

• I assume closes #73480

Describe the solution

Dissect npc::wield_better_weapon() into its constituent evaluation and iteration parts so it can be reused elsewhere

When NPC is deciding to throw a weapon, check if this is their best weapon. If it is, rate it as unavailable for throwing purposes.

Describe alternatives you've considered

This doesn't try to cover some situation where the NPC MUST throw their only item to survive, but I don't consider that very likely?

Testing

Loaded the save from #71526 and run towards the bandits, got a hatchet and baseball bat thrown at me. Applied PR, tried again, nothing is thrown. Bandit with a glock still shoots me on approach in both circumstances.

Ran [npc_ai] and [npc_attack] tests locally, passed.

Mergers, reviewers, everyone else: Some additional manual testing around grenades/thrown weapons would be nice

Additional context

[RenechCDDA]

Hmm looks like this will cause an intermittent test failure. Let's hold off on merging this until I can resolve that.

[RenechCDDA]

That was simple enough to resolve, just allowed them to throw if they had backups of the weapon they were throwing. So a NPC with a bag of rocks will leave the last one to bash your skull in with, but throw the rest if possible. Will also work if the NPC has a bag of throwing axes, or javelins, or something strange like that.