fix: add support for re-authentication in Murena account settings

Description

With SSO-enabled Account Manager, there was no way to reauthenticate a Murena account using OAuth and SSO. (Refer to the issue for screen record.)

This MR enables the user to reauthenticate a Murena account using OAuth.

Screenshots

Technical details

Tests

Issues

https://gitlab.e.foundation/e/os/backlog/-/issues/3377

10 commandments of code review

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Summary by CodeRabbit

• New Features

  • Improved account setup and re-authentication flows by providing additional context, such as account name hints and re-authentication status, during login and account addition.

• Refactor

  • Simplified and centralized account selection and creation logic for easier maintenance.
  • Streamlined login blocking and authentication checks for better code clarity and consistency.

• Bug Fixes

  • Enhanced handling of re-authentication scenarios to ensure smoother user experience during account updates or migrations.