ATO-732: Add login_required error code description

[BenjaminWCO]

Why

We're adding support for a new "login_required" re-authentication error code. See:

• https://govukverify.atlassian.net/wiki/spaces/LO/pages/4092952611/Re-Auth+-+Incorrect+details+provided+by+user#Orchestration
• https://govukverify.atlassian.net/jira/software/c/projects/ATO/boards/390?assignee=712020%3Ac05df90e-0476-43ae-85c5-1cd3a261173b&selectedIssue=ATO-732

What

• Add a entry to the error code table documenting when an RP might receive this code and what it means.

Technical writer support

Yes, please provide feedback on any corrections or improvements.

How to review

• Check change communicates what is intended clearly.
• Check for typos.
• Confirm if change is consistent with existing documentation.
• Confirm if update to change log was necessary.

Changelog

• [x] If this change is significant (for example, launching a new feature or deprecating a feature), you should update the changelog found at partials/_changelog.erb under the heading 'Documentation updates'.#

Confirm

• [ ] I have checked if any docs change here also requires updates to other repositories (ADRs / RFCs, README.md, Team Manual, elsewhere in these docs)
• [x] Where there is any overlap I have updated or opened a PR for corresponding changes

[sabrinaharris]

Thanks! Not ready for merging as this needs tech writer support. I'll check who can pick this up 👍

[PippaClarkGDS]

hi @BenjaminWCO let me know when the changes have been made and I'll do another review

[BenjaminWCO]

hi @BenjaminWCO let me know when the changes have been made and I'll do another review

Thanks @PippaClarkGDS , taking a look now.

[BenjaminWCO]

Hi @PippaClarkGDS, I've made those changes. Thanks for the help. Just made one small tweak to your recommendations regarding the email as you suggested might be the case. Let me know if you have any other thoughts.

[PippaClarkGDS]

Nice @BenjaminWCO - @sabrinaharris will be able to add her review now

[BenjaminWCO]

Thanks @ethanmills, @PippaClarkGDS . I'll wait for confirmation from @sabrinaharris and the changes to be in production before I merge this.

[BenjaminWCO]

Hi, @sabrinaharris, fixed the change log conflict.