Ensure sidebarTrigger.nextSibling is not null when showing/hiding toolbar

I'm moving this back to needs work as the changes seem to only be in the dist folder. Also we would need an MR to run all the tests 👀

I am faced with problem when page has no elements with css class 'meta-sidebar__trigger'.
(error - Cannot read properties of null (reading 'querySelector'))
sidebarTrigger = document.querySelector(".meta-sidebar__trigger") need to wrap conditions to avoid js error.

This still needs a MR and I think we can simplify the code down just to sidebarTrigger.nextSibling?.innerHTML = showLabel;

@rahunak

I am faced with problem when page has no elements with css class 'meta-sidebar__trigger'.

In which situation would that be? I can't think of any we provide out of the box 🤔
If you use the content hook you might want to switch to the sticky action hook instead (?)

I have created a MR with the changes. The build fails, but I do not know why. The branch seems up to date.

I have also tested the patch, which works fine.

Pipeline is also running successfully now.

Thanks!