All hooked workflows' errors are dumped to terminal

### What happened? (You can include a screenshot if it helps explain)

Needs `flow` to reproduce.

Is reproducible by commenting out the observation config line in the rft example.
In rft.ert, add double hyphen to this line to comment it out:
`-- OBS_CONFIG obs.txt`
Then run a test run, either by gui:
`ert gui test-data/ert/rft_example/rft.ert`
or by cli:
`ert test_run test-data/ert/rft_example/rft.ert`

### What did you expect to happen?

No traceback in terminal

Reproduce with test-data/ert/rft_example/rft.ert after commenting out the OBS_CONFIG line, using either `ert gui test-data/ert/rft_example/rft.ert` or `ert test_run test-data/ert/rft_example/rft.ert`. Trace how hooked workflow errors are reported, then verify that the test run completes without a traceback in the terminal.

Written by the indexing model from the issue text.