Updating FunctionsNetHost (dotnet isolated worker) to 1.0.9

[kshyju]

Updating FunctionsNetHost (dotnet isolated worker) to 1.0.9. Azure/azure-functions-dotnet-worker#2552
Updated a test(which uses the actual worker configs) to reflect this change.

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
  • Otherwise: Link to backporting PR -[in-proc] Updating FunctionsNetHost (dotnet isolated worker) to 1.0.9 #10263
• 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 [in-proc] Updating FunctionsNetHost (dotnet isolated worker) to 1.0.9 #10263
• 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

Additional PR information

[kshyju]

Many tests depend on the worker config provided by the referenced worker packages. The new DNI worker config requires a specific environment variable (WEBSITE_PLACEHOLDER_MODE) to be present. If this variable is absent, the worker will be skipped. Therefore, the tests need to include this environment variable. I am currently working on fixing them.