Resolve issue with autocomplete pre-filling back link

[JamieCleare2525]

Context

Back links on the Provider and School onboarding (Claims and Placements) "Check your answers" pages need to redirect back to the "New" onboarding forms, with the user's selection pre-filled.
Once directed back, and the form is pre-filled, clicking continue should submit the form and take the user back to the "Check your answers" page.

Developer Insight

Due to an issue with the accessible-autocomplete, additional javascript and changes to how options are rendered needed to be added to app/javascript/controllers/autocomplete_controller.js. Otherwise, the result of using defaultValue results in an undefined option appearing in the dropdown.
See alphagov/accessible-autocomplete#424 for more details.

Changes proposed in this pull request

• Back links on the "Check your answers" pages for Schools and Providers (Claims and Placements) redirect back to the "New" onboarding forms, with pre-filled user input (School or Provider name).
• PreviousSearch tag added to html, to allow stimulus to assign the Provider/School name and id to the correct inputs.
• Methods added to Provider/School Onboarding Form classes to easily assign back params.

Guidance to review

• Follow steps to onboard to a school/provider until you reach the "Check your answers" page.
• Once on the "Check your answers" page, Click the "back" link at the top of the page.
• You should be redirected back to the "New" onboarding form for the school/provider.
• The user input for the "New" onboarding form should be pre-filled with the school/provider name.
• Clicking "Continue", without searching should return the user to the "Check your answers" page for the same school/provider.

Link to Trello card

https://trello.com/c/e5SwYKuK/138-fix-back-links-on-providers-schools-onboarding-pages-to-pre-fill-the-search-input-new-page-with-users-input

Screenshots

Screen.Recording.2024-01-31.at.16.21.18.mov

[github-actions]

Review app track and pay deployed to https://track-and-pay-188.test.teacherservices.cloud was deleted
Review app school placements deployed to https://manage-school-placements-188.test.teacherservices.cloud was deleted

[elceebee]

I think this looks great. I found one little edge case, see video. If you clear the field and then click continue (without entering new data), the old data is persisted.

Honestly, unless it's a really easy fix, I don't think it's really worth doing.

And I'm perfectly happy with that little sliver of an empty drop-down -- better than [undefined undefined]. We are working with a far-from-perfect component here, so this might be the bets we can do for now.
https://github.com/DFE-Digital/itt-mentor-services/assets/44073106/a24e6200-d1ea-4201-a71f-302de0222db8

[CatalinVoineag]

Great effort! The autocomplete is a pain to work with