DLSV2-548 Further accessibility fixes following internal and external retest

[kevwhitt-hee]

JIRA link

DLSV2-548

Description

• Adds aria-label attributes to various links (Clear, Preview Resource etc)
• Introduces aria-required attribute to NHS design system form control view components
• Moves dom structure of self assessment radio button questions to use fieldset

Doesn't:

• Remove hidden inputs that are necessary for the working of the web application
• Address the red-herring warning in Wave that hidden inputs don't have labels - they shouldn't
• Doesn't address warnings that two consecutive links are to the same place - they aren't, there is just a mobile and non-mobile version of the same link in breadcrumbs only one of which is ever visible

Screenshots

Attach screenshots on mobile, tablet and desktop.

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Developer checks

(Leave tasks unticked if they haven't been appropriate for your ticket.)

I have:

• Run the formatter and made sure there are no IDE errors.
• Written tests for the changes (accessibility tests, unit tests for controller, data services, services, view models, etc)
• Manually tested my work with and without JavaScript. Full manual testing guidelines can be found here: https://softwiretech.atlassian.net/wiki/spaces/HEE/pages/6703648740/Testing
• Updated/added documentation in Swiki and/or Readme. Links (if any) are below:
  • doc_1_here
• Updated my Jira ticket with information about other parts of the system that were touched as part of the MR and have to be sanity tested to ensure nothing’s broken.
• Scanned over my own MR to ensure everything is as expected.