Fixes items preventing other switch in effects

[AlexOn1ine]

Fixes #5427

Despite the description of the issue, this was an issue with items. After a switch in when items are triggered they blocked all other effect from happening. The problem was the place they were invoked from. To fix this I Introduced ITEMEFFECT_ON_SWITCH_IN_FIRST_TURN which will only work for first turn effects and ITEMEFFECT_ON_SWITCH_IN will be used for the rest. By passing the caseID as the argument we can easily switch between the scripts we want to run.

Tests were provided by @PhallenTree

[Pawkkie]

I think this is a massive improvement to readability along with the bugfix. Approving but not merging in case you'd like another battle-script-centric reviewer to give it a once over first, though feel free to just merge when you wake up :)

small change incoming

[AlexOn1ine]

Sorry @Pawkkie, I found an other minor optimization to do so dismissed the review. Feel free to approve and merge again.

[Bassoonian]

Conflict