Add functionality to cast a spell

[Carifio24]

This PR adds functionality, exposed via a button in the spell window controller, to cast a spell. The effect of this is to use a slot of the appropriate level for the current character. The basic logic breakdown is as follows:

If the spell has rules for higher level casting, and the character has available slot(s) of the spell's level or higher, a popup controller allows selecting which spell level to cast
If the spell doesn't have higher level rules and the character's only available slots are of a higher level, a popup controller is presented asking if the user wants to upcast (for no benefit)
If the spell doesn't have higher level rules and the character has a slot of the appropriate level, a slot of that level is expended
Otherwise, a Toast message informs the user of the issue with casting (the character either doesn't have any slots, or any available slots, of an appropriate level)

This PR also fixes an issue where component flags weren't being used when filtering spells.