Multiclass Requirements not Enforced

[DivertedCircle]

Describe the bug
Multiclass restrictions are only taking into consideration the stat requirement of the class to be gained whereas it should be considering that, as well as requirements for all other classes taken.

To Reproduce
Steps to reproduce the behavior:

1. Create a new character. Use manual entry to set all stats to 10, except for Strength and Intelligence. Set these 2 stats to 13.
2. Select the Wizard class. Click the 'Add Levels in Another Class'. Barbarian and Fighter show available on the list.
3. Lower Intelligence to 12.
4. Barbarian and Fighter still appear as options to multiclass into, even though the Intelligence requirement for Wizard is no longer met.

Expected behavior
A warning should show indicating you do not meet the requirements to multiclass out of Wizard.