Fixes #29093 - change from superficial copy to deep copy of fields

[adiabramovitch]

No description provided.

[yifatmakias]

Thanks @adiabramovitch ,
Notice that the hammer_cli_foreman tests are failing with this error:

[ofedoren]

FYI: I'm currently working on a little bit different approach for option creation and this anonymous class will disappear :) So, 👍 for the solution, but it should wait a bit before we get rid of this class.

[ofedoren]

Thanks, @adiabramovitch! Since this change doesn't break tests for plugins anymore we can finally merge it :)

[ekohl]

Looks like this broke nightly again, just like in #345 (comment): https://ci.theforeman.org/job/foreman-nightly-rpm-pipeline/1160/tapResults/

not ok 6 import motd puppet class
# (in test file fb-test-puppet.bats, line 64)
#   `hammer proxy import-classes --name $(hostname -f)' failed with status 70
# Error: singleton can't be dumped

[ofedoren]

Looks like this broke nightly again, just like in #345 (comment): https://ci.theforeman.org/job/foreman-nightly-rpm-pipeline/1160/tapResults/

@ekohl, yeap, I'm aware of that: #353

[ekohl]

Thanks!