IllegalPluginAccessException when using EvtByReflection for non-event classes

**Describe the bug**
As the title says, an IPAE is thrown when a class that doesn't implement Event is used as input.

**To reproduce**
```
import:
  java.util.function.Consumer


on Consumer:
  broadcast "%event%"
```
**Expected behavior**
I would expect the addon to do type-checking before casting or passing around the input, and throw an error if applicable.
