Modify Button Behaviour When enable-submissions Flag is Disabled

[chrstinalin]

Fixes: mozilla/addons#15090

Description

when enable-submissions is disabled, now:

1. Disables the 'create a theme' button
2. Addon submission buttons are disabled and a warning is displayed banner style with the flag note (if any).

Testing

1. Deactivate the enable-submissions waffle flag (everyone should be = True by default).
2. User should be unable to make new submissions and warned via the disabled button.

Checklist

• Add #ISSUENUM at the top of your PR to an existing open issue in the mozilla/addons repository.
• Successfully verified the change locally.
• The change is covered by automated tests, or otherwise indicated why doing so is unnecessary/impossible.

[KevinMind]

@chrstinalin could you reassign review. I'll be on PTO next week and don't want to block you.

[eviljeff]

I might be missing some context here, but why are we doing the disabling, and rendering the error, in javascript? We know submissions are disabled when the template is rendered so add the logic to disable the buttons and display the message in the template?

We can test the error message is visible and the button disabled in tests too that way

[chrstinalin]

I honestly can't recall if I had a reason for this, I think it may have been the natural progression of my original barebones fix... That solution makes alot more sense.

[eviljeff]

Some nits in the test code, and it works fine. I want to get a second opinion on the UI though - exposing the reason in a tooltip you have to mouse-over to seee feels too hidden to me. Can you include a screenshot of what it looks like for reference? (you've already included one)

[eviljeff]

@diox you requested the changes in your PR review - was this what you intended? I'm not sure a tooltip you have to hover to expose is obvious enough?

[diox]

I'm no UX/Product person but I think it should be a bit more obvious. My idea was to prevent submissions while at the same time still showing a page that looks somewhat normal, because the error page you otherwise get from the decorator is a bit too generic/empty (it's good as a fallback for anyone trying to bypass the more user-friendly error).

[chrstinalin]

@diox My initial fear with directly putting the reason on the page is if the reason is longer than usual (which may not happen) and possibly look weird.

Though IIRC there's somewhere in DevHub that use a banner-style information section, which might work better? I can't seem to find it, though.

[diox]

Search for site-notice (it displays the content of the zadmin.models.Config named site_notice which can be set in the admin)