Add `contains_group` method in python api for `NodeTree` type, cleanup
`ntreeHasTree` function, reuse `ntreeHasTree` in more place in code.
The algorithm has been changed to not recheck trees by using set.
Performance gains from avoiding already checked node trees:
Based on tests, can say that for large files with a huge number
of trees, the response speed of opening the search menu in the
node editor increased by ~200 times (for really large projects
with 16 individual groups in 6 levels of nesting). Group insert
operations are also accelerated, but this is different in some cases.
Pull Request #104465
d411be8a99