Enable variable simulation in Journeys Playground for conditional testing

Business problem

Currently, users are unable to fully test Journeys that rely on specific conditions because the Playground does not support the input of variables or media during the testing phase.

Wished result

The ability to mock or input specific data—such as email addresses, media, phone numbers, and custom variables—within the Journeys Playground to simulate different customer scenarios and verify that all conditional routing logic functions as intended.