Make Potion.isBadEffect() available server-side

In the Minecraft source, they made Potion.isBadEffect() client-side-only because it's only used for rendering tooltips. (or at least that's the best reason I can come up with...)

I would like to be able to use it for more than that.

Forestry has an apiarist's suit that protects against negative bee effects. Some of the bee effects use potions. I want to use Potion.isBadEffect() to determine if the effect is negative and should be protected against.
```java
EntityPlayer player = ...
int duration = ...
if (potion.isBadEffect()) {
	// Reduce duration based on the amount of apiarist armor worn
}
 
player.addPotionEffect(new PotionEffect(potion.getId(), duration, 0));
```