Handle a device already being connected with the BlueZ Dbus backend

[bdraco]

Fixes #992

[dlech]

Please add a changelog entry too.

[dlech]

For the record, there are a couple of pitfalls with this:

1. This will now allow disconnecting devices that we don't "own" the connection to. If the device is used by the OS (e.g. a keyboard or mouse), this could be problematic.
2. Many devices that are already connected won't be advertising, so may not be discoverable with BleakScanner so additional changes like those suggested in Device may already be connected when calling connect with BlueZ #992 (comment) may be needed to fully make use of this change.

In spite of these, this seems like a step in the right direction.

[bdraco]

2. Many devices that are already connected won't be advertising, so may not be discoverable with BleakScanner so additional changes like those suggested in Device may already be connected when calling connect with BlueZ #992 (comment) may be needed to fully make use of this change.

The workaround I'm using for that is https://github.com/Bluetooth-Devices/bleak-retry-connector/blob/e8bb72257a4e58a55a839525b2762d7db8dcab0c/src/bleak_retry_connector/__init__.py#L246

Note: its not so pretty and I'd like to get rid of it

[bdraco]

This also need to handle the device not being in the history anymore

2022-09-10 13:07:42.089 ERROR (MainThread) [aiohomekit.utils] Failure running background task: Task-10942
Traceback (most recent call last):
  File "/usr/local/lib/python3.10/site-packages/aiohomekit/utils.py", line 29, in _handle_task_result
    task.result()
  File "/usr/local/lib/python3.10/site-packages/aiohomekit/controller/ble/pairing.py", line 411, in _process_disconnected_events
    results = await self.get_characteristics(list(self.subscriptions))
  File "/usr/local/lib/python3.10/site-packages/aiohomekit/controller/ble/client.py", line 75, in _async_wrap
    return await func(*args, **kwargs)
  File "/usr/local/lib/python3.10/site-packages/aiohomekit/controller/ble/pairing.py", line 707, in get_characteristics
    return await self._get_characteristics_without_retry(characteristics)
  File "/usr/local/lib/python3.10/site-packages/aiohomekit/controller/ble/pairing.py", line 111, in _async_wrap
    return await func(self, *args, **kwargs)
  File "/usr/local/lib/python3.10/site-packages/aiohomekit/controller/ble/pairing.py", line 714, in _get_characteristics_without_retry
    await self._populate_accessories_and_characteristics()
  File "/usr/local/lib/python3.10/site-packages/aiohomekit/controller/ble/pairing.py", line 583, in _populate_accessories_and_characteristics
    await self._ensure_connected()
  File "/usr/local/lib/python3.10/site-packages/aiohomekit/controller/ble/pairing.py", line 323, in _ensure_connected
    self.client = await establish_connection(
  File "/usr/local/lib/python3.10/site-packages/aiohomekit/controller/ble/connection.py", line 48, in establish_connection
    return await retry_establish_connection(
  File "/usr/local/lib/python3.10/site-packages/bleak_retry_connector/__init__.py", line 410, in establish_connection
    await client.connect(
  File "/usr/local/lib/python3.10/site-packages/bleak_retry_connector/__init__.py", line 138, in connect
    connected = await super().connect(
  File "/usr/local/lib/python3.10/site-packages/bleak/backends/bluezdbus/client.py", line 158, in connect
    if not manager.is_connected(self._device_path):
  File "/usr/local/lib/python3.10/site-packages/bleak/backends/bluezdbus/manager.py", line 610, in is_connected
    return self._properties[device_path][defs.DEVICE_INTERFACE]["Connected"]
KeyError: 'org.bluez.Device1'

[bdraco]

Still doing testing. Will do another turn once done testing

[bdraco]

Additional testing looks good