Go back to without popping each page

[niimima]

Description of Change

Adding GoBackAsync methods without popping each page and NavigateFromAsync methods without recreating a page.

Bugs Fixed

• fixes GoBackTo without popping each page #2818

API Changes

Added:

• Task INavigationServiceExtensions.GoBackAsync(string viewName);
• Task INavigationService.GoBackAsync(string viewName, INavigationParameters parameters);

Changed:

• INavigationServiceExtensions.Task GoBackAsync(this INavigationService navigationService)

Behavioral Changes

No changes. Only additions of features. We have added casts due to errors in existing extension methods, but there are no changes in behavior.

PR Checklist

• Has tests (if omitted, state reason in description)
• Rebased on top of master at time of PR
• Changes adhere to coding standard

[niimima]

@dansiegel
I am in the process of implementing the API according to this comment: #2818 (comment)

As far as debugging goes, it seems to be working reasonably well. However, I am uncertain about the possible use cases and whether the behavior is truly correct. Additionally, I am unsure about the variations I should create in unit tests and struggling with deciding which class to target for unit tests (it should be the PageNavigationServiceFixture class, but it is not currently the subject of unit testing).

I apologize for reaching out amidst your busy schedule, but I would appreciate any advice you can provide.

[dansiegel]

Be sure to add Unit tests for the new APIs. It would also be good to update the E2E app for manual testing and validation.

[dansiegel]

Also would suggest you break this up into 2 PR's one for GoBack and one for NavigateFrom

[niimima]

Thank you for your advice.
This is my first pull request involving a feature change, so it might take a bit of time, but I'll give it a try. This PR will be focused on the GoBack.

[niimima]

@dansiegel 
Implemented end-to-end test: ba06722 , also implemented unit tests: a6e14b5.

[dansiegel]

Thanks for the PR @niimima