Revert debugger launch behaviour to default profile

Summary:
Reverts the debugger launch flow to use the default `ChromeLauncher` profile. This is the approach used in the current `--experimental-debugger` experiment and by Expo.

This is motivated after a review of the tradeoffs of a guest profile — which allow us to programatically quit the browser process, however takes over system URL handling.

Changelog: [Internal]

Differential Revision: D57619542

packages/dev-middleware/src/utils/DefaultBrowserLauncher.js

@@ -52,22 +52,11 @@ const DefaultBrowserLauncher: BrowserLauncher = {
     );
     const launchedChrome = await ChromeLauncher.launch({
       chromeFlags: [
-        ...ChromeLauncher.Launcher.defaultFlags().filter(
-          /**
-           * This flag controls whether Chrome treats a visually covered (occluded) tab
-           * as "backgrounded". We launch CDT as a single tab/window via `--app`, so we
-           * do want Chrome to treat our tab as "backgrounded" when the UI is covered.
-           * Omitting this flag allows "visibilitychange" events to fire properly.
-           */
-          flag => flag !== '--disable-backgrounding-occluded-windows',
-        ),
         `--app=${url}`,
         `--user-data-dir=${userDataDir}`,
         '--window-size=1200,600',
-        '--guest',
       ],
       chromePath,
-      ignoreDefaultFlags: true,
     });
 
     return {