[Homebrew] Allow Publishing of Homebrew With Mixed Spell Entries

Currently if a homebrew race, sub-class etc. contains a spell entry that has a mixture of SRD (free) and non-SRD (paid) spells such that a player is able to choose one from a list, it will prevent the homebrew from being published due to the presence of the paid content.

However, since there is a mixture of paid and free spell options this should not prevent the homebrew from being published, as users without access to the paid content can still fully use the homebrew, as they can still choose from the free spell options in the list.

Spell entries that contain only paid spell options would prevent sharing of the homebrew as normal (as these will cause the homebrew to be broken if a player does not have the necessary paid content). Only when there is at least one free spell that meets the minimum requirements of the spell entry (is of a level low enough to always be selected) in the list should publishing be permitted.

This is related to a previous issue of mine, but is a simpler alternative, as this change to the behaviour will make it possible for homebrew authors to offer their own fallback(s) for paid content when it isn't available. It should also be a relatively simple fix to the behaviour that prevents homebrew publishing.