Sigmon 82 i earth plot update

Context

• Project README link: https://gitlab.cern.ch/LHCData/lhc-sm-api/-/blob/master/README.md
• Story reminder: https://its.cern.ch/jira/browse/SIGMON-82
• Task details: https://its.cern.ch/jira/browse/SIGMON-82

What was done

• keypoints of the implementation: --> Refactor of the Pc13kARqAnalysis class. --> Update the analyze_i_earth_pcnt_pc method

TODO

QA

• code was unit tested

Review objectives

• assessment of code functionality
• assessment of code quality
• identifying potential refactorings / logic common to other projects
• knowledge sharing