Add warnings on how to handle offline emulators

Summary:
My emulators stopped showing up, but I noticed they were still listed in adb devices as 'offline'. Seems to be a weird ADB issue, changing the developer settings on the emulator fixed that for me, so linked to the SO answer where I found the solution.

Changelog: Added warning about offline emulators in ADB

Reviewed By: nikoant

Differential Revision: D30957786

fbshipit-source-id: 5468a983b5364c0fe868610978c09382f6b43d91

desktop/app/src/server/devices/android/androidDeviceManager.tsx

@@ -193,6 +193,10 @@ export class AndroidDeviceManager {
           tracker.on('add', async (device) => {
             if (device.type !== 'offline') {
               this.registerDevice(client, device);
+            } else {
+              console.warn(
+                `[conn] Found device ${device.id}, but it has status offline. If this concerns an emulator and the problem persists, try these solutins: https://stackoverflow.com/a/21330228/1983583, https://stackoverflow.com/a/56053223/1983583`,
+              );
             }
           });