Remove packing option from optionfile.yaml

[MircoValentiniECMWF]

Removed packing option from the configuration.

Description

Contributor Declaration

By opening this pull request, I affirm the following:

• All authors agree to the Contributor License Agreement.
• The code follows the project's coding standards.
• I have performed self-review and added comments where needed.
• I have added or updated tests to verify that my changes are effective and functional.
• I have run all existing tests and confirmed they pass.

🌈🌦️📖🚧 Documentation 🚧📖🌦️🌈
https://sites.ecmwf.int/docs/dev-section/multio/pull-requests/PR-286

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 33.12%. Comparing base (bc78165) to head (c6a8bc4).

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #286      +/-   ##
===========================================
- Coverage    33.51%   33.12%   -0.39%     
===========================================
  Files          379      375       -4     
  Lines        42642    42388     -254     
  Branches      1837     1837              
===========================================
- Hits         14292    14043     -249     
+ Misses       28350    28345       -5     

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

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.