Physical Android: two-finger gestures end with an ACTION_UP carrying both pointers, which Android rejects, while the tool reports success #1628

[Diplomat, Opus 5.5]: On a physical Android device (kind: "device", android_device controller), gesture-pinch, gesture-rotate and a two-finger gesture-custom report success, but Android rejects the gesture's final event.

Repro (a Pixel API 34 emulator connected as adb connect 127.0.0.1:5559, so it is kind: "device", on the #1397 head 1e40265):

1. Run gesture-pinch with centre (0.5, 0.6) and distance 0.1 -> 0.3. It returns pinched: true.
2. logcat shows InputDispatcher: Injection failed: invalid event: invalid pointer count 2.
3. On the next gesture-tap, logcat shows InputDispatcher: Conflicting pointer actions: Down received while already down or hovering. On API 34 the tap still lands.

On API 37 the #1397 author saw both pointers stay down after this and every later touch refused until a reboot (#1397 (comment)). That was on the same controller code, reached through the emulator fallback.

Cause: the android_device controller's send_touch (radon device_controller/android_device.rs) lifts both fingers with one ACTION_UP that carries both pointers, instead of an ACTION_POINTER_UP followed by an ACTION_UP.

Impact: on a user's phone a pinch or rotate is reported as done, even though Android rejected its last event. On recent Android it locks all touch input on the phone. #1397 rejects two-finger gestures only for an emulator that fell back to this controller (singleTouchOnly is set only when adbFallback), so physical phones still send it.