Fix failing start_powershell test

start_powershell recently started failing on the v3.x branch with host v3.0.15149. This test was disabled after we determined it was a test issue. Adding a delay to give enough time for the result to be ready didn't seem to help. From the output of the failed runs, it almost looks like the host never starts, but gets stuck during function creation:

```
stdout: Running: > D:\a\1\s\artifacts\win-x86\func.exe init . --worker-runtime powershell --managed-dependencies false
stdout: Writing profile.ps1
stdout: Writing .gitignore
stdout: Writing host.json
stdout: Writing local.settings.json
stdout: Writing C:\Users\VssAdministrator\AppData\Local\Temp\sta0rk5v.y51\.vscode\extensions.json
stdout:
stderr:
stdout: Running: > D:\a\1\s\artifacts\win-x86\func.exe new --template "Http trigger" --name HttpTrigger
stdout: Use the up/down arrow keys to select a language:
stdout: 1. PowerShell
stdout: 2. Powershell
stderr:
stdout: Choose option:
stdout:
```