fix: incorrect callback association when choosing --emg-mode=3 and with IMU

[iomz]

The callback registration is not associated right:

future: <Task finished name='Task-685' coro=<MyoClient.notify_callback() done, defined at /Users/iomz/ghq/github.com/iomz/dl-myo/myo/core.py:375> exception=TypeError('can only concatenate tuple (not "IMUData") to tuple')>
Traceback (most recent call last):
  File "/Users/iomz/ghq/github.com/iomz/dl-myo/myo/core.py", line 393, in notify_callback
    await self.on_imu_data(IMUData(data))
  File "/Users/iomz/ghq/github.com/Interactions-HSG/MyoKTROS/src/myoktros/client.py", line 207, in on_imu_data
    line = ",".join(map(str, (time.time(),) + imu))
TypeError: can only concatenate tuple (not "IMUData") to tuple
2023-08-23 09:11:20,027 asyncio  ERROR: Task exception was never retrieved
future: <Task finished name='Task-686' coro=<MyoClient.notify_callback() done, defined at /Users/iomz/ghq/github.com/iomz/dl-myo/myo/core.py:375> exception=NotImplementedError()>
Traceback (most recent call last):
  File "/Users/iomz/ghq/github.com/iomz/dl-myo/myo/core.py", line 407, in notify_callback
    await self.on_emg_data(emg)
  File "/Users/iomz/ghq/github.com/iomz/dl-myo/myo/core.py", line 358, in on_emg_data
    raise NotImplementedError()
NotImplementedError