Fix / refactor FunctionsHostingConfigOptionsTest

[jviau]

Issue describing the changes in this PR

resolves #10889

Pull request checklist

IMPORTANT: Currently, changes must be backported to the in-proc branch to be included in Core Tools and non-Flex deployments.

• Backporting to the in-proc branch is not required -- TODO
  • Otherwise: Link to backporting PR
• My changes do not require documentation changes
  • Otherwise: Documentation issue linked to PR
• My changes should not be added to the release notes for the next release
  • Otherwise: I've added my notes to release_notes.md
• My changes do not need to be backported to a previous version
  • Otherwise: Backport tracked by issue/PR #issue_or_pr
• My changes do not require diagnostic events changes
  • Otherwise: I have added/updated all related diagnostic events and their documentation (Documentation issue linked to PR)
• I have added all required tests (Unit tests, E2E tests)

Additional information

Refactors FunctionsHostingConfigOptionsTest to stabilize and improve the tests.

1. Removes ConfigureDefaultTestWebScriptHost usage
   • This is the main source of instability as it made these effectively integration tests. Using that host brings in a lot of other components. The unstable issue observed was bundle resolution was running and intermittently failing! It was even calling our CDN. Outbound HTTP calls in unit tests is not good.
2. Splits the large Property_Validation test into two, one for validating access and another for validating expectations. Also converts these into a theory using MemberData.
3. Removes unnecessary delays, host starts, and more from tests