Ignore duplicate events in a much less hacky way

Immediately reduce tech debt.

tests/pilot_recorder.py

@@ -74,18 +74,13 @@ class PilotRecorder():
         self.next_after_exit: Callable[[], None] | None = None
 
         recorder = self
-        hack = True
         async def on_event(self: PaintApp, event: Event) -> None:
-            # FIXME: every event is received in duplicate
-            # Ignoring every other event is a really stupid way to fix it,
-            # but I don't know why it's happening.
-            nonlocal hack # "oh no remote hacking"
-            hack = not hack # "psh this hack isn't really a hack"
-            if hack:
-                await original_on_event(self, event)
-                return
             # Record before the event is handled, so a clicked button that closes a dialog,
             # removing the button from the DOM, will still be in the DOM when we record it.
+            # Don't record forwarded events, because then every action is duplicated.
+            # I don't know if recording only forwarded events would make more sense,
+            # I don't claim to understand the forwarding scheme.
+            if not event._forwarded:
                 recorder.record_event(event)
             await original_on_event(self, event)
         self.app_on_event = on_event