Respect backoffice login returnPath regression

[jrunestone]

Prerequisites

Fixes #15686 (was originally fixed in 2022/2023)

Description

See issue for detailed info and how to reproduce.

Looks like while implementing the new login screen a typo was made that means the redirect url is never carried on.

There is however another part to this: in some situations when you try to directly go to a protected backoffice page (e.g. /umbraco#/settings) while not being logged in and not using basic authentication as in the issue, you are redirected to the login page but without the returnPath query parm. The redirect itself is done here https://github.com/umbraco/Umbraco-CMS/blob/v13/contrib/src/Umbraco.Web.BackOffice/Controllers/BackOfficeController.cs#L141 but I'm not sure how/where the hash part of the query is carried on on the client.

[github-actions]

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[mikecp]

Hi @jrunestone,

Thanks for providing a fix for this issue (again 😅 ?). A member of the core collaborators team will have a look at it soon.

Cheers and have a great week!