fix(item-update): visibility of range spanning items not always correct

[ChristianKrebel]

This is the copy of a PR to the origin Repo because we cannot wait for it to be merged. Original PR can be found here: visjs#1846

Items starting before the visible range and ending after it were not always shown if zoomed in too much because of the binary search used for it. I tried to fix the conditions but I could not get it to work with a binary search (maybe someone has a better way?). Also, different approaches like spatial index logic fixed the problem but did not improve performance. So I kept it simple and removed the binary search case for items that have an end time and always brute force check them for visibility. This may worsen performance when having many items with end times but in my manual testing (private repo) it is not performant either way.

Question: Should we make this fix optional per config because it may have a bigger impact?

Module: timeline/component/group

Fixes visjs#1657