imu: make it part of InputState

Putting this here to see what CI has to say. Not super happy with this, input state seems to expand/copy too much

python_payload/st3m/power.py

@@ -21,7 +21,7 @@ class Power:
     def _update(self) -> None:
         ts = time.ticks_ms()
         if ts >= self._ts + 1000:
-            # Sampling takes time, don't do it too oftern
+            # Sampling takes time, don't do it too often
             self._battery_voltage = self._battery_voltage_sample()
             self._ts = ts