Use declaration markdown

[thomasiles]

Switch declarations to markdown not text

Trello card: https://trello.com/c/b8rdhhe4/2836-support-markdown-in-declaration-field

This PR switches to using the markdown editors for declarations in English and Welsh.

The forms:convert_declaration_text_to_markdown has been run in dev, prod and staging and the runner is displaying the declaration_markdown field.

This PR stops using the original field, declaration_text and only uses declaration_markdown. delcaration_text is not dropped from the database or form documents. This allows rollback and also re-running the forms:convert_declaration_text_to_markdown if for some reason we need to.

The declaration_text field can be ignored and dropped and field removed from form_documents in a future, cleanup PR.

Things to consider when reviewing

• Ensure that you consider the wider context.
• Does it work when run on your machine?
• Is it clear what the code is doing?
• Do the commit messages explain why the changes were made?
• Are there all the unit tests needed?
• Do the end to end tests need updating before these changes will pass?
• Has all relevant documentation been updated?

[chao-xian]

Looks good and work on the review app

[DavidBiddle]

Code looks good, tested locally and it all works with the migration task and looks as expected on the live/archived and Welsh pages 🎉

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

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