fix: Session restore list index overflow when using a plugin that modifies the slot count

[iLynxcat]

Fixes #51

Problem

• Plugins like InvSee++ may modify the amount of slots in a player's inventory
• We hardcode the slot count at the vanilla limit of 41
• This causes an overflow when saving -> restoring sessions to/from admin-state.yml

Solution

• Pass the full Player reference down to AdminState#fromConfig
• Use the lower value of these two for the array's size
  • Number of items in saved list
  • Total slots in Player's inventory
• This should now gracefully handle mismatches

To-do

• Test with InvSee++ installed
  • Verify bug on 1.5.1 release
    Not sure on an exact replication, can't seem to make it produce more than 41 items. Pushing this fix anyway for verification by the user
  • Verify fix at 7afc63d