fix: move port validation and waiting logic into proxy server

[anthonychu]

Move wait for port logic into the proxy.

• Running swa start http://localhost:3000 --run "npm:start" --app-location frontend now works properly
• Moving the wait for API to just before starting the proxy means most of the function app output now prints before the proxy starts. This ensures that this message will no longer be hidden by the function app output:

  [swa] Available on:
  [swa]     http://192.168.187.166:4280
  [swa]     http://0.0.0.0:4280
  [swa] 
  [swa] Azure Static Web Apps emulator started. Press CTRL+C to exit.
  

[manekinekko]

There is already a global flag called isApiDevServer:

Suggested change

	const isApi = Boolean(SWA_CLI_API_LOCATION && SWA_CLI_API_URI);
	if (isApi) {
	if (isApiDevServer) {

[anthonychu]

I wanted to wait whether it’s using dev server or if someone passed a path to the API folder, so that the output from func is printed before the proxy starts.

[manekinekko]

LGTM.