Fail early on missing encoding profile

[geichelberger]

If the encoding profile is missing on a remote node (opencast-worker), the workflow failed with a misleading exception. This PR introduces an exception and fails early instead of ignoring a missing profile and failing later.

• have a concise title
• close an accompanying issue if one exists
• be against the correct branch
• include migration scripts and documentation, if appropriate
• pass automated tests
• have a clean commit history
• have proper commit messages (title and body) for all commits

[mliradelc]

Seems fine for me, but first I need to try it

[mliradelc]

I tried, works as expected, but I don't understand something.

Should fail at the beginning of the task, or at the start of the Encode WoH?

[mliradelc]

Tested, works as expected