Merge onboarding experiments integration branch (#9571)

* Add onboarding survey page

* Add onboarding new analytics events to mixpanel allowlist

* [web] Try Premium prompt

* moved try-premium code to overleaf-integration

* fixed sheet styling

* Add onboarding flow redirect handling to registration handlers (#9462)

* Add redirect logic for onboarding flow after registration

* Update UPGRADE_PROMPT_URL

* Cleanup style of OverleafAuthenticationController

* Refactor finishLogin calls to call wrapped function in OverleafAuthenticationController

* Refactor user properties/onboarding flow redirect into finishLogin wrapper

* Fix async/await calls after refactoring

* Update tests for finishLogin refactoring

* Don't redirect to upgrade prompt if user has premium via commons

Co-authored-by: Miguel Serrano <mserranom@users.noreply.github.com>
GitOrigin-RevId: 7c392aa6949f99fa909f9ca4e4baad4c4d4ff6be

services/web/test/unit/src/Subscription/SubscriptionControllerTests.js

@@ -404,6 +404,7 @@ describe('SubscriptionController', function () {
           title: 'thank_you',
           personalSubscription: 'foo',
           premiumFeaturesDiscoverability: false,
+          postCheckoutRedirect: undefined,
         })
         done()
       }