Show toast on API errors

[mariusandra]

(PR hijacked by @paolodamico , ignore @mariusandra 's face next to the text)

Changes

Closes #3525. This PR brings back toast errors when something goes wrong, with a few key differences.

• We will now show only one error at a time. Part of the problem we had before is that you would open a page and 4 toasts would pop up, which felt quite overwhelming.
• We don't show errors for some specific endpoints that we know don't affect the user experience (e.g. preflight) or have special error handling (e.g. insights).
• Show a more detailed error.
• We will show a more detailed error message when a request fails due to a network error or blocked request.
• Opens Papercups if available.
  

Examples:

All feedback welcome!

Checklist

• All querysets/queries filter by Organization, by Team, and by User
• Django backend tests
• Jest frontend tests
• Cypress end-to-end tests

[paolodamico]

@mariusandra if you don't mind I'll hijack your PR, make some tweaks and get this out, want to get this in before the code freeze.

[mariusandra]

Please!

[paolodamico]

Ready for a review @mariusandra!

[mariusandra]

Code looks good and considering I was already happy with how these toasts were before they were removed, I can only approve!

Because of this bias I'd say @timgl should also say if the approach works for him.

It's good that we can easily add actions to be ignored. This will help keep the interface noise free.

There's just one UX issue that I think should be solved, best illustrated by a screencast:

If we show only one error, then I'd always like to see the last error shown to me, as that's probably the most urgent one.

[paolodamico]

Agreed @mariusandra, I've updated it so that the last error is the one that's actually shown. Will wait for @timgl's input on the UX before merging.