bugfix(report): improves instability alignment in metrics reporter

[sverweij]

Description

• reserves an extra character of room for displaying metrics in the metrics reporter
• also removes a superfluous toString statement from the same

Motivation and Context

Some locales put a space between the number and the percentage sign. The max width of the I column didn't account for that - resulting in misalignment between 3 and < 3 number percentages:

100 %
90 %
 1 %
100 %

After the fix it looks normal in these locales again:

100 %
 90 %
  1 %
100 %

How Has This Been Tested?

• green ci
• adapted unit tests

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• Documentation only change
• Refactor (non-breaking change which fixes an issue without changing functionality)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• 📖

  • My change doesn't require a documentation update, or ...
  • it does and I have updated it

• ⚖️

  • The contribution will be subject to The MIT license, and I'm OK with that.
  • The contribution is my own original work.
  • I am ok with the stuff in CONTRIBUTING.md.