There is no error when typing a web app name with "test-"

[v-mengwe]

trafficstars

OS: Win10 Build Version: 20220225.1 Regression: Preview release

Repro Steps:

1. Click "Create New Web App.." button -> Select a subscription -> Type a web app name with "test-".
2. Check whether there is an error when typing a web app name with "test-".

Expect: There is an error when typing a web app name with "test-".

Actual: There is no error when typing a web app name with "test-".

More Info: Fail to create the web app "test-" with an error "The host name webappname azurewebsites.net is invalid."

[nturinski]

This will be fixed by updating the @microsoft-vscode-azext-appservice extension