Ability to disable "Create a new story" button from sidebar

[tuckergordon]

Is your feature request related to a problem? Please describe.

While the "create a new story" button in the sidebar is a nice idea, it has led to confusion on our team and we have encountered similar issues to those described in #28377

The current documentation for disableSaveFromUI is within a section that has a screen recording of the sidebar button being used, which would seem to suggest that setting disableSaveFromUI to true would disable the button. disableSaveFromUI only impacts Controls though and does not remove the button from the sidebar.

Describe the solution you'd like

Either of

1. disableSaveFromUI also removes the "Create a new story" button from the sidebar
2. Allow users to set the showCreateStoryButton, perhaps within preview parameters or addons.setConfig()

Describe alternatives you've considered

No response

Are you able to assist to bring the feature to reality?

no

Additional context

No response