[D8] Should menu items and their hierarchy be revisionable?

[klonos]

This may be related to #1475 (forward revisions, and also revisions in general).

The respective issues in d.org are:

https://www.drupal.org/project/drupal/issues/2880152 (implemented in 8.7.x)
https://www.drupal.org/project/drupal/issues/3035089 (follow-up to previous issue - currently postponed)

So here's the problem I'm trying to address (reported in the #australia-nz Drupal Slack channel):

Editing a node, changing its menu position, and saving as a draft (using Workflows). I get the error: You can only change the parent menu item for the published version of this content ...I can avoid the error if my workflow allows transitions from published -> published. But that sorta misses the point of workflows.

Just wanted to make sure if this is an issue in Backdrop, and if not then make sure that we account for this use case with our revisioning.