limit command output to important lines

[mcalmer]

What does this PR change?

The full result is so big, that internal buffers seems to be filled and not the complete output is returned.
This cause no "SLES" keyword is included in the output and the test always hit the timeout.

This PR return only the important lines and make the test pass again.

GUI diff

No difference.

• DONE

Documentation

• No documentation needed: only internal and user invisible changes

• DONE

Test coverage

• No tests: already covered

• DONE

Links

Tracks https://github.com/SUSE/spacewalk/pull/22784

• DONE

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[nodeg]

I did some small tests

suma-43-srv:~ # spacecmd -u admin -p admin api sync.content.listProducts > test_long
INFO: Spacewalk Username: admin
INFO: Connected to https://suma-43-srv.mgr.suse.de/rpc/api as admin
WARNING: The traditional stack is deprecated as of the release of SUSE manager 4.3. It will be unsupported in the next major release, version 4.4 or greater. Consider migrating to salt minions before this release.

suma-43-srv:~ # spacecmd -u admin -p admin api sync.content.listProducts | grep SLES > test_short
INFO: Spacewalk Username: admin
INFO: Connected to https://suma-43-srv.mgr.suse.de/rpc/api as admin
WARNING: The traditional stack is deprecated as of the release of SUSE manager 4.3. It will be unsupported in the next major release, version 4.4 or greater. Consider migrating to salt minions before this release.

suma-43-srv:~ # cat test_long | wc -l
10115

suma-43-srv:~ # cat test_short | wc -l
111
suma-43-srv:~ #

Furthermore, the step works again. Tested on a local HEAD environment.

  Scenario: Wait for refresh of list of products to finish # features/core/srv_first_settings.feature:40
      This scenario ran at: 2023-10-16 11:17:04 +0200
    When I wait until mgr-sync refresh is finished         # features/step_definitions/command_steps.rb:693
      This scenario took: 4 seconds

Thank you for diving into this and preparing a fix, mc!