Replace test.com with special-use domain name.

[guidorice]

Related Issue(s): #

Fixes #732

Description:

Use stac.test instead of test.com, following https://www.rfc-editor.org/rfc/rfc6761.html

PR Checklist:

• Code is formatted (run pre-commit run --all-files)
• Tests pass (run scripts/test)
• Documentation has been updated to reflect changes, if applicable
• This PR maintains or improves overall codebase code coverage.
• Changes are added to the CHANGELOG. See the docs for information about adding to the changelog.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.55%. Comparing base (037fd73) to head (3ab25f2).
⚠️ Report is 630 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #769   +/-   ##
=======================================
  Coverage   94.55%   94.55%           
=======================================
  Files          79       79           
  Lines       11647    11647           
  Branches     1372     1372           
=======================================
  Hits        11013    11013           
  Misses        455      455           
  Partials      179      179           

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