1.18 crash with tooltip edge cases

[Siphalor]

In certain vanilla and non-vanilla cases the world of the tooltip item method is actually null.
In the decompiled code this parameter is therefore also annotated with the @Nullable annotation.

The following line causes an NPE in these circumstances:

Nomad-Books/src/main/java/net/zestyblaze/nomadbooks/item/NomadBookItem.java

Line 381 in b4fd96f

if (dimension.isPresent() && dimension.get() == world.dimension()) {

A simple null check should do the trick :)

Originally reported as a compatibility issue with Mouse Wheelie in Siphalor/mouse-wheelie#187 (comment).