[repo] Extend NugetAudit by indirect references

[Kielek]

Follow up #5784

Changes

Brings defaults from .NET9.
Opportunistic update of other tests packages.

System.Text.Json references can be removed when Microsoft.Coyote will be released microsoft/coyote#507

Merge requirement checklist

• CONTRIBUTING guidelines followed (license requirements, nullable enabled, static analysis, etc.)
• [ ] Unit tests added/updated
• [ ] Appropriate CHANGELOG.md files updated for non-trivial changes
• [ ] Changes in public API reviewed (if applicable)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 86.30%. Comparing base (6250307) to head (cbe8e59).
Report is 303 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5812      +/-   ##
==========================================
+ Coverage   83.38%   86.30%   +2.91%     
==========================================
  Files         297      257      -40     
  Lines       12531    11150    -1381     
==========================================
- Hits        10449     9623     -826     
+ Misses       2082     1527     -555     

Flag	Coverage Δ
unittests	?
unittests-Project-Experimental	86.18% <ø> (?)
unittests-Project-Stable	86.18% <ø> (?)
unittests-Solution	86.03% <ø> (?)
unittests-UnstableCoreLibraries-Experimental	85.76% <ø> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

see 213 files with indirect coverage changes