Description of problem:
If we add extra callback plugins in ansible configuration, they are ignored while running remote ansible jobs and hence output of callback plugins is not there in the UI. 

Consider we add timer, profile_tasks plugins which show some extra time statistics for the playboook run 
-------------------
# grep callback_whitelist /usr/share/foreman-proxy/.ansible.cfg
callback_whitelist = foreman, timer, profile_tasks
-------------------

When any ansible remote job is run like package\service action, the output of added callback plugins is not there in the satellite as they are overridden in the code for a remote command :
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# egrep CALLBACK_WHITELIST ./lib/foreman_ansible_core/command_creator.rb
      defaults['ANSIBLE_CALLBACK_WHITELIST'] = '' if rex_command?
-----------------

When running assigned ansible roles, the output of plugins is present as CALLBACK_WHITELIST is not oveerriden in this case.

Version-Release number of selected component (if applicable):
6.4

How reproducible:
Always

Steps to Reproduce:
1. Add timer, profile_tasks callback plugins to /usr/share/foreman-proxy/.ansible.cfg
2. Run a ansible provider based remote job and output of callback plugins is missing there

Actual results:
Callback plugins are overriden to empty value

Expected results:
It should read list of callback plugins from configuration and ignore only "foreman" plugin for a rex job.

Additional info: