Remove form change function footguns

[AsparagusEduardo]

Description

Currently, when form changes are checked, the functions return SPECIES_NONE if they won't change form in the current conditions and this is checked on all their uses. However, should a user forget to check for SPECIES_NONE, their mon will essentially be deleted due to setting their species to SPECIES_NONE. This PR aims to fix this by changing the functions into returning the current species, along with updating their checks.

Already tested with item hold, weather and Gigantamax form changes, so I'd be safe to say that all of them work correctly. Feel free to test indepth if you desire.

People who collaborated with me in this PR

@AlexOn1ine for letting me know of this potential issue.

Things to note in the release changelog:

• GetBattleFormChangeTargetSpecies, GetFormChangeTargetSpecies and GetFormChangeTargetSpeciesBoxMon now return the current species of the Pokémon instead of SPECIES_NONE as a precaution to avoid accidental deletions of Pokémon when using these functions.

Discord contact info

AsparagusEduardo

[AlexOn1ine]

I think this is a good change overall. Avoid the mentioned potential footgun is useful for users.