Perform S-bit rate scan from high to low thresholds

Description

As the title says, this merge request aims at performing the S-bit rate scan from high to low thresholds.

Details are in the commit message:

It has been noticed that the VFAT3 S-bit rate can end up in a "locked
up" state. More specifically, when performing the S-bit rate scan from
low to high thresholds, the S-bit rate may not smoothly decreases but
instead drops sharply. The final threshold may or may not be impacted.
Nevertheless, this is considered as abnormal behavior.

This commit swaps the scan direction, scanning from high to low
thresholds. Intense testing on ME0 has revealed a constant and good
performances. No breaking changes in the analysis suite are expected
either.

Related Issue

How Has This Been Tested?

Thoroughly tested on the ME0 stack test beam & QC8 setups.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

requested review from @cgalloni

assigned to @lpetre

approved this merge request

added 12 commits

• 333ac061...95b9f17d - 11 commits from branch main
• 0e3cd4cc - Perform S-bit rate scan from high to low thresholds

Compare with previous version

enabled an automatic merge when all merge checks for 0e3cd4cc pass

mentioned in commit 8c9415ff

merged