Fix failing proposal tests

[lahdeero]

🎩 What? Why?

I think some tests related to dynamic attachment uploads failed because when there were multiple uploads in same test. This was probably happening because after first successfully upload there was "progress-bar.filled" although the new upload was not ready yet. Here we check that the "progress-bar" is filled for the file currently being uploaded.

📌 Related Issues

#8681

Testing

Trying to run tests in CI multiple times.

Locally everything seems fine:

cd decidim-proposals
bundle exec rspec spec/system/edit_proposal_spec.rb -e "can add many images many times"
bundle exec rspec spec/system/proposals_fields_spec.rb -e "sets the card image correctly with zero weight"

♥️ Thank you!

[andreslucena]

Seems like the last change did the trick @lahdeero, thank you and congratulations on finding it!

I'm relaunching the specs for these a couple of times just to be sure before merging.

Should we leave the rest of changes, or just this last one?

[lahdeero]

@andreslucena I did some cleaning, these changes should be enough 🙏