feat(web): improved user onboarding (#18782)

* wip

* added user metadata key

* wip

* restructure onboarding system and add initial locale

* update language card and fix translation updating

* remove prints

* new card formattings

* fix cursed unmount effect

* add OAuth route onboarding

* remove required admin auth for onboarding

* delete the hotwire button

* update open-api files

* delete import

* fix failing oauth onboarding fields

* fix e2e test

* fix web e2e test

* add onboarding to user registration e2e test

* remove todo

this was a holdover during dev and didn't get deleted

* fix server small tests

* use onDestroy to save settings rather than a bind:this

* change to false for isOnboarded

* fix other auth small test

* provide type annotation in user factory metadata field

* remove onboardingCompelted from UserDto

* move translations to onboarding steps array and mark as derived so they update

* break language selector out into its own component as per @danieldietzler suggestion

* remove hello header on card

* fix flixkering on server privacy card

* label/id fixes

* openapi

---------

Co-authored-by: Alex Tran <alex.tran1502@gmail.com>

mobile/openapi/lib/api.dart

@@ -177,6 +177,8 @@ part 'model/o_auth_callback_dto.dart';
 part 'model/o_auth_config_dto.dart';
 part 'model/o_auth_token_endpoint_auth_method.dart';
 part 'model/on_this_day_dto.dart';
+part 'model/onboarding_dto.dart';
+part 'model/onboarding_response_dto.dart';
 part 'model/partner_direction.dart';
 part 'model/partner_response_dto.dart';
 part 'model/people_response.dart';