Allow Spell Item use while Blind and Dazzled

By allowing potions, scrolls, and wands to be used while Blind and
Dazzled, the power of both immediately drop. The primary concern is the
length of Blind on unbuffed targets: now unbuffed targets can drink
Eagle Eyes potions while blind, or pop Winds scrolls, or even use wands.

I want to talk about wands for a second. There's a world of options here.
With this change, you can Purify wand yourself, although they're weak power,
only come from Chieftains, and require positive karma. Time spent
Purify wanding is probably time spent standing still getting beatdown.
On the flip side, you can also use offensive wands while Dazzled, assuming
you're good enough to use a wand and aim it correctly with impaired vision.
So while Shals have the advantage of using Purify wands, they can't
stop you from using Hold, Dement, and other wands right back at them.

This change is naturally suited to the recent upgrades to spell items. They now
stack and never expire, so players can farm or make potions as needed
and carry them for important moments.

This is also a parallel weakening of Purge: Shals can't stop you from
drinking a potion because they don't have Hold. You can't completely
rebuff yourself with potions, but you can certainly get up one or two
buffs that really matter.

This proposal:
- nerfs no spells directly at all
- offers a new reaction option so players aren't just running around
like a chicken with its head cut off
- opens up potions, scrolls, and wands to a MUCH larger variety of tactics