[Devops] Run metrics job from forks

[karl-richter]

🔬 Background

• Currently the metrics job does not run on forks due to issues with the CML library (comments from forks to the main repo are not supported).

🔮 Key changes

• In a recent PR, the CML library introduced the feature to comment on pr's from forks.
• This PR contains the change to comment from a fork to the target pr.

📋 Review Checklist

• I have performed a self-review of my own code.
• I have commented my code, added docstrings and data types to function definitions.
• I have added pytests to check whether my feature / fix works.

Please make sure to follow our best practices in the Contributing guidelines.

[karl-richter]

Closed #910

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.21%. Comparing base (4ea077a) to head (652f6d2).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1113   +/-   ##
=======================================
  Coverage   88.21%   88.21%           
=======================================
  Files          41       41           
  Lines        5355     5355           
=======================================
  Hits         4724     4724           
  Misses        631      631           

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[karl-richter]

Note: This pr does not fully fix the problem of the metrics job failing when executed from a forked repository. Github requires the agent to be logged in when commenting on pull requests of another repository. However, this pr provides a cleaner implementation of commenting to pull requests when executed from a branch within the main repository. Therefore I would recommend to merge this pr now and create a seperate pr when the metrics job should also succeed in forked repositories.