Make Folia detection method more resilient to shading the server platform

[A248]

Currently, MorePaperLib checks for the presence of a certain Folia API class to determine whether Folia is being used.

This can break if another plugin has shaded the entire Folia server platform, which is most certainly a bug in its own right and drastic for the server.

Nevertheless, this means a MorePaperLib-dependent plugin can sometimes break as an additional consequence. See, for example, A248/LibertyBans#283 . To resolve this, we might check for methods on existing classes (like the method mentioned in the linked NoSuchMethodError) instead of a certain class on the classpath.