Keep the job and state through a recreate

[zeevy]

Fixes #187 and #188. #191 was tested and closed as not a real crash.

#188 - stale state after the switch from Bluetooth to USB

• restartInUsbMode() starts UsbConnectionActivity and then finishes. Android destroys the old activity after the new one has read MachineStatusListener, FileSenderListener and ConsoleLoggerListener, and the old onDestroy() replaced them. The USB screen kept the old objects.
• Now GrblActivity.onCreate resets them only on a fresh start (savedInstanceState == null), and onDestroy no longer does.

#187 - a fold, rotation or resize stopped a running job

• Android 16 ignores the portrait lock and resizeableActivity=false on large screens, so the activity is recreated. onDestroy() then stopped the streaming service and the serial service, and sent $10=1.
• Now those run only when isFinishing(). The serial service is started, so it outlives the unbind and the new activity binds to it again.
• After a recreate during a job the new activity now shows "Connected" when the link is up, sets keep screen on again, and does not show the battery dialog (it covered the Stop button).

Checked

• Emulator (API 37), with throwaway builds (not committed) that enable the file and start buttons with no machine:
  • A fold, rotation or resize stops a running job and resets the app state #187: pick a file, resize to tablet size. Old code: file gone, new USB service instance. New code: file kept, same service instance.
  • USB screen keeps stale state after the switch from Bluetooth #188: deny Bluetooth so the app falls back to USB, pick a file, Start. Old code: "No gcode file selected" and 0/0 rows. New code: the service streams the file (6/6).
• Pixel 6a (Android 17) with GRBL 1.1f on USB OTG, no motors, this code under a separate package name: an 83-line job, dark mode switched twice mid-job (two activity relaunches). The streaming and USB services kept the same instances, the job ran to 100% (83/83, 1:53), the toolbar stayed "Connected", no battery dialog, no crash.
• ./gradlew build passes.

Not covered: on a phone (not a large screen) a display density or size change makes Android restart the whole process, because the activities are non-resizable. That stops a job too, but it is system behaviour, not this code.