[#5039] Fix email registration errors

[vaszig]

Closes #5039

Changes

• Email registration used nonField errors for a combination of fields and these were not shown on the frontend. Fixed these by showing them on the top of the modal.

Checklist

Check off the items that are completed or not relevant.

• Impact on features

  • Checked copying a form
  • Checked import/export of a form
  • Config checks in the configuration overview admin page
  • Problem detection in the admin email digest is handled

• Release management

  • I have labelled the PR as "needs-backport" accordingly

• I have updated the translations assets (you do NOT need to provide translations)

  • Ran ./bin/makemessages_js.sh
  • Ran ./bin/compilemessages_js.sh

• Dockerfile/scripts

  • Updated the Dockerfile with the necessary scripts from the ./bin folder

• Commit hygiene

  • Commit messages refer to the relevant Github issue
  • Commit messages explain the "why" of change, not the how

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.73%. Comparing base (a4e2c38) to head (31b74f0).
Report is 14 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #5098   +/-   ##
=======================================
  Coverage   96.73%   96.73%           
=======================================
  Files         774      775    +1     
  Lines       26657    26662    +5     
  Branches     3468     3468           
=======================================
+ Hits        25787    25792    +5     
  Misses        608      608           
  Partials      262      262           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[viktorvanwijk]

Works as expected :). As you already pointed out, though, might be nice if there is a solution which will work for all option forms, not only this plugin.

[sergei-maertens]

Accepting this as it is - I think with the UX rework we'll have the chance to fix this properly so that you don't have to think about it at all anymore.

[sergei-maertens]

Backports:

• 3.0.x: 4b1ecdf
• 2.8.x: skipped as it didn't have the UX rework yet