Improve changed state tracking ability in the RESPECT editor.

[szczz]

Description

Discussed in the 01/14/2025 Platform meeting.

RESPECT does not have a reliable way of tracking whether changes have been made to a storyline product. For example, if you load a storyline, create a new slide, and then delete that slide, RESPECT will indicate that there are unsaved changes even though the product is in the exact same state as when it was loaded. This leads to issues and requires workaround for other systems as discussed in #459.

We should introduce proper state tracking, so that we can avoid future issues and workarounds.

Proposed solution

@yileifeng has proposed the following initial idea:

An initial idea is to store a separate copy of the last saved version of config slides and the metadata object inside a store upon loading in a product. Then, we could replace the current watcher behavior that updates the save status indicator with a deep object comparison method (e.g. Lodash).

Related Issues

#123