[Workflows] Http Request Event should not store tenant prefix

[jptissot]

When exporting a workflow with the Http Request Event, the url is exported with the tenant prefix. We have to manually edit the exported json to remove the prefix. It would be better if the tenant prefix was not stored.

[jptissot]

After investigating, I realized that the tenant prefix is not even used by the workflow. However, the HttpRequest Activity token needs to be generated on the tenant itself. So I suggest to do the following improvements:

• Modify the forms module Action field to support liquid syntax, or the ~/ prefix. Or allow the form to target the workflow HttpRequest Activity directly.
• Modify the recipe export logic of the workflow and form to automatically generate the JS variables for the Workflow ID and HttpRequest event Activity ID.