[Feat]: Manage Oauth with /preview links like /view links

[lanedsmu]

When browsing to lowcoderurl/apps/appID/view, authentication happens as expected: user is redirected to the appropriate auth provider (oauth or email or whatever) and then back to the app url after authentication.

With /preview URLs (and with URLs that don't have anything after the app ID), however, the behavior appears not to have been updated, and the user is redirected in ways I don't quite understand yet. Behavior definitely does not mirror the behavior in /view.

Instead, we'd like the login behavior to be consistent, and to match what's done with /view URLs.

Additionally, it may be worth pointing out that when going to a particular app URL, there may not actually be a reason to prompt for an email address before taking the user to the auth screen: with an app specified in the URL, there's already a defined destination org, so the email prompt is a bit superfluous.