percentage savings calculation fix in post-processing

[JanghyunJK]

Pull request overview

• this PR is merging to Wenyi's branch: wenyi/euss_r3
• overriding correcting percentage calculation in comstock.py #265
• in our comstock wide csv (or the equivalents with the new sampling), we have columns calculating percentage savings
• these columns have percentage unit based on comstock column definitions csv
• however, the value itself is fraction/ratio. so not %.
• this PR is trying to fix this.
• also, our default savings distribution/violin plots are actually showing the right unit of % because there's a multiplier happening in the plotting_mixin.py.
• so I'm also trying to align things altogether in this PR.
• below are new figures (percentage savings plot only) from the std perf scenario

cc-ing: @JieXiong9119 @mpraprost @amyeallen1

Pull Request Author

This pull request makes changes to (select all the apply):

• Documentation
• Infrastructure (includes apptainer image, buildstock batch, dependencies, continuous integration tests)
• Sampling
• Workflow Measures
• Upgrade Measures
• Reporting Measures
• Postprocessing

Author pull request checklist:

• Tagged the pull request with the appropriate label (documentation, infrastructure, sampling, workflow measure, upgrade measure, reporting measure, postprocessing) to help categorize changes in the release notes.
• Added tests for new measures
• Updated measure .xml(s)
• Register values added to comstock_column_definitions.csv
• Both options_lookup.tsv files updated
• 10k+ test run
• Change documentation written
• Measure documentation written
• ComStock documentation updated
• Changes reflected in example .yml files
• Changes reflected in README.md files
• Added 'See ComStock License' language to first two lines of each code file
• Implements corresponding measure tests and indexing path in test/reporting_measure_tests.txt, test/workflow_measure_tests.txt, or test/upgrade_measure_tests.txt
• All new and existing tests pass the CI

Review Checklist

This will not be exhaustively relevant to every PR.

• Perform a code review on GitHub
• All related changes have been implemented: data and method additions, changes, tests
• If fixing a defect, verify by running develop branch and reproducing defect, then running PR and reproducing fix
• Reviewed change documentation
• Ensured code files contain License reference
• Results differences are reasonable
• Make sure the newly added measures has been added with tests and indexed properly
• CI status: all tests pass