Platform fails to start if defining a message origin for an application that provides activators

[danielwiehl]

Describe the bug

The message origin defines where a message from an application must originate to be accepted and delivered by the host. Specifying a different origin may be necessary, for example, if integrating microfrontends into a rich client. The rich client then intercepts messages from applications and "forwards" them to the (remote) host. Thus, such messages originate from the host rather than the application.

However, since activator microfrontends are embedded directly in the host and communication between the host and activator is not bridged, they still originate from the application and not the host, and thus will be rejected by the host.

Expected behavior

Messages from and to activators are not rejected.

Environment

Please complete the following information:

SCION Microfrontend Platform version: 1.0.0-rc.3