Fix ici_filter

[rhaschke]

ici_filter should filter stdout for a given string. However, on error, the full output should be shown.
While the original implementation of industrial_ci realizes the former, the latter fails.

My implementation (8c72e0f) works locally but fails on GHA (showing everything all the time, not filtering at all). For this reason I reverted to the original ici implementation (02ff659) for now. Need to further debug...

Maybe GHA redirects stdout + stderr of the main process?