Update default value for content files argument

[jmborr]

This commit changes the default value for the content_files and pv_files arguments to a comma-separated string. This update ensures compatibility and consistency in the handling of default content file lists across different modules.

Description of the changes

Check all that apply:

• added release notes (if not, provide an explanation in the work description)
• updated documentation
• Source added/refactored
• Added unit tests
• Added integration tests

References:

• Links to IBM EWM items:
• Links to related issues or pull requests:

Manual test for the reviewer

Check list for the reviewer

• release notes updated, or an explanation is provided as to why release notes are unnecessary
• best software practices
  • clearly named variables (better to be verbose in variable names)
  • code comments explaining the intent of code blocks
• All the tests are passing
• The documentation is up to date
• code comments added when explaining intent

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.51%. Comparing base (fa43a9e) to head (c91e637).

Additional details and impacted files

@@           Coverage Diff           @@
##             next       #7   +/-   ##
=======================================
  Coverage   89.51%   89.51%           
=======================================
  Files           3        3           
  Lines         124      124           
=======================================
  Hits          111      111           
  Misses         13       13           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.