Support Web authentication cancel scenario

[lbalmaceda]

Changes

Now when pressing the back key (or closing the browser/webview activity) the callback will receive a call to onFailure with an AuthenticationException.
On this exception one could call isAuthenticationCanceled() to determine if the error was caused because of the user canceling an authentication process.

The change is compatible with browser authentication and also with webview authentication (deprecated).

References

Closes #127

Testing

• This change adds unit test coverage

• This change adds integration test coverage

• This change has been tested on the latest version of the platform/language or why not

Checklist

• I have read the Auth0 general contribution guidelines

• I have read the Auth0 Code of Conduct

• All existing and new tests complete without errors

[h-mubarak]

Is this branch merged with the current available auth0 version(1.15.2)? I am using this version but not able to see the changes.

[TWiStErRob]

@h-mubarak on GitHub PRs there's a commit when the PR is merged. Click on the commit hash above your comment (d492d28) and you'll see the details. If there's a version tag after the branch icon, it's included in that release. See for example this older PR merge commit: e82f4de

[h-mubarak]

Thanks for detail info @TWiStErRob, Shall i know when this merge will get versioned so that i can use it.

[sklr13]

@TWiStErRob I am also interested in this feature because without it I will have a huge and ugly workaround. Can you please provide the information when it will be approximately released?

[lbalmaceda]

Released under 1.16.0.