[SIGMON-467] ack Zinurs feedback

Context

• task: https://its.cern.ch/jira/browse/SIGMON-467

What was done

• sources without U_DIODE removed
• STATUS.I_REF changed to ILOOP.I_REF for RUN3 data

TODO

• ?

QA

• http://sonar/project/issues?branch=SIGMON-467_ack_zinurs_feedback&id=lhc-sm-api&resolved=false
• test updated

Review objectives

• ? assessment of code functionality
• ? assessment of code quality
• ? identifying potential refactorings / logic common to other projects
• ? knowledge sharing
• ? getting help to understand a piece of code