Upgrade CLI, restore prev status check value (#39077)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/39077

Follow-up to https://github.com/facebook/react-native/pull/38988.

- Upgrade to RN CLI `12.0.0-alpha.11`.
- Restore previous value check against `/status` response in test scripts (restored in above CLI alpha).

Changelog: [Internal]

Reviewed By: motiz88

Differential Revision: D48432629

fbshipit-source-id: 175241ad75676281f4638e179873b2ce32f0ea3e

scripts/testing-utils.js

@@ -117,12 +117,6 @@ function isPackagerRunning(
       silent: true,
     }).stdout;
 
-    // TODO(huntie): Temporary string match in JSON response. We will revert
-    // this endpoint back to "packager-status:running" in the next CLI alpha.
-    if (status.includes('"status":"running"')) {
-      return 'running';
-    }
-
     return status === 'packager-status:running' ? 'running' : 'unrecognized';
   } catch (_error) {
     return 'not_running';