Detect when blocks are clickable

[ZacSharp]

This currently uses uncached reflection on the pathing thread, and I'd like to hear some other opinions on possible solutions.

The obvious solution would be a Reference2BoolOpenHashMap<Class<?>>, but due to not wanting to synchronize things that cache would have to live in CalculationContext despite caching static data. Instead we could use mixin to move the cache to a final field on Block instances, which has the only drawback of caching per Block instance, not subclass (and adding a public method to an mc class). Caching per subclass should be possible by using a custom transformer to directly write the value into the bytecode of the getter method, but that's clearly overkill. Using mixin to do this is probably not possible.