When local.settings.json is absent, runnig func host start does not work for newer worker models #3544 (Refreshed Branch Changes)

[VineethReyya]

Issue describing the changes in this PR

-> when local.settings.json is absent.
Scenario1: running 'func host start' will Display Available WorkerRuntime on the screen and user can select the Runtime from the list so the FUNCTION_WORKER_RUNTIME setting is added and start hosting the function app
Scenario2: running 'func host start --{WorkerRuntime}' will add FUNCTION_WORKER_RUNTIME setting and start hosting the function app.
resolves #3544

Pull request checklist

• My changes do not require documentation changes
  • Otherwise: Documentation issue linked to PR
• My changes do not need to be backported to a previous version
  • Otherwise: Backport tracked by issue/PR #issue_or_pr
• I have added all required tests (Unit tests, E2E tests)

[VineethReyya]

Issue describing the changes in this PR

-> when local.settings.json is absent. Scenario1: running 'func host start' will Display Available WorkerRuntime on the screen and user can select the Runtime from the list so the FUNCTION_WORKER_RUNTIME setting is added and start hosting the function app Scenario2: running 'func host start --{WorkerRuntime}' will add FUNCTION_WORKER_RUNTIME setting and start hosting the function app. resolves #3544

Pull request checklist

• My changes do not require documentation changes

  • Otherwise: Documentation issue linked to PR

• My changes do not need to be backported to a previous version

  • Otherwise: Backport tracked by issue/PR #issue_or_pr

• I have added all required tests (Unit tests, E2E tests)

@liliankasem PR was failed to build in azure pipeline. after looking into the reason for failure I came to know that you have worked on starttest.cs. Now I refreshed my branch with latest changes and created a new PR. could you please review when you have free moment of time.