Add markdown declaration to check your answers page, if the form has it

[thomasiles]

Add markdown declaration to check your answers page, if the form has it

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

We are changing the declaration from a text field, rendered with basic formatting, to a markdown field. This matches the "what happens next" and guidance fields, which already use markdown.

The declaration is currently stored in a field in the form and form document as declaration_text. We will add a new field called declaration_markdown which will replace the text version. To support the migration between the two, the runner needs to support both.

This PR renders the declaration_markdown if it's present. If it's not, it uses declaration_text as usual.

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?

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
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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