Add text filter to PC spellcasting tab

[Noisyink]

Closes #19937 (text portion; advanced filter to follow).

Added to PC sheets only - Can add to NPC sheets as well if needed but spell lists tend to be smaller on NPCs so figured it wasn't needed.

Test plan

• PC spellcasting tab: type in the new search input, non-matching spell rows hide, clearing restores

[CarlosFdez]

Screenshot of end result?

[Noisyink]

Screenshot of end result?

Advanced filter is a different PR, so ignore that it's there for this one

[Noisyink]

Just realised you probably want more than that - I can hide the headers for ranks with no finds if we want? It'd reduce some of the clutter.

[CarlosFdez]

I'm not sure, people may want to drag/drop it? Maybe if the entry has nothing? I dunno. I'll leave it up to you.

The padding is off though. Its too close to the navigation. Compare with the other tabs. Inventory for example has a 10px top padding.

[Noisyink]

I'm not sure, people may want to drag/drop it? Maybe if the entry has nothing? I dunno. I'll leave it up to you.

The padding is off though. Its too close to the navigation. Compare with the other tabs. Inventory for example has a 10px top padding.

Might throw a post in the discord, get some feedback. Will mark the padding for fix 🤙