Adapt unit tests for PR 42 Add custom formatting for TimeSpan

[DaveyJonesBitPail]

Description

There were some minor UT adaptations that I thought I had pushed before merging #42.

• Freeze Mock of ITimeFormatter to return empty string within AggregateStatisticsViewModelTests because we want to test invariant of formatting.
• Remove ShouldBeEquivalent options to ignore Duration when comparing AggregateStatisticsViewModel and AggregateStatistics record.

Type of change

• 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 not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Describe the tests that you ran to verify your changes.
Provide instructions to reproduce.

Checklist:

• I followed the Contributing Guidelines.
• I did a self-review.
• I commented my code, particularly in hard-to-understand areas.
• I updated the documentation.
• I updated the version of czicompress following the README (Versioning) depending on the type of change
  • Bug fix -> PATCH
  • New feature -> MINOR
  • Breaking change -> MAJOR
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.

[codecov]

Codecov Report

Merging #43 (487e36a) into main (f03a169) will not change coverage.
The diff coverage is n/a.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #43   +/-   ##
=======================================
  Coverage   77.72%   77.72%           
=======================================
  Files          59       59           
  Lines        1917     1917           
  Branches      122      122           
=======================================
  Hits         1490     1490           
  Misses        403      403           
  Partials       24       24           

Components	Coverage Δ
czicompress	66.75% <ø> (ø)
czishrink	80.45% <ø> (ø)