Describe the bug
The validation rules of the proposals form are stepped between them in the administration panel

To Reproduce
Steps to reproduce the behavior:

1. Go to 'admin/participatory_processes/X/components/x/manage/proposals/new'
2. Type some text on the title field
3. See error
   

Expected behavior
Now that we have specific validation messages, we no longer need the error alert "There's an error in this field."

Extra data (please complete the following information):

• Device: Desktop
• Device OS: All
• Browser: All
• Decidim Version: 0.23.0.dev
• Decidim installation: https://staging.decidim.codegram.com