[#378] Fixed error message with screen reader.

[febdao]

Fixed: #378

Jira ticket:

• https://salsadigital.atlassian.net/browse/CIVIC-1990

Checklist before requesting a review

• I have formatted the subject to include the issue number
  as [#123] Verb in past tense with a period at the end.
• I have provided information in the Changed section about WHY something was
  done if this was a bespoke implementation.
• I have performed a self-review of my code.
• I have commented on my code, particularly in hard-to-understand areas.
• I have added tests that prove my fix is effective or that my feature works.
• I have run new and existing relevant tests locally with my changes,
  and they have passed.
• I have provided screenshots, where applicable.

Changed

1. Add the aria-describedby attribute to all inputs that may require an error message.
2. When an input is in an error state, inject the error container with an error message.
3. Add the aria-invalid attribute to all required fields with a value of "false". Update this to "true" when the input is in an error state.

Screenshots

[richardgaunt]

@febdao I have some questions about the use of aria-invalid and its position within the component

[febdao]

The CR has been fixed but this PR is no longer required as the issue has been fixed by this PR #480