Cannot connect city hub on macOS 12

[dlech]

Describe the bug
What is the problem?

After flashing firmware from https://beta.pybricks.com, the hub will not connect when clicking the Bluetooth button. After a while the following error is shown:

GATT Server is disconnected. Cannot retrieve services. (Re)connect first with `device.gatt.connect`.

To reproduce
Steps to reproduce the behavior:

1. Install macOS 12 (beta)
2. Install Chrome web browser (tried both Version 93.0.4577.82 (Official Build) (x86_64) and Version 96.0.4648.0 (Official Build) canary (x86_64))
3. Go to https://beta.pybricks.com
4. Install firmware
5. Click on Bluetooth button to connect, select the hub from the list and click pair
6. Bluetooth button spins busy for a while then an error message is shown

Expected behavior
It should connect as before

Screenshots

[dlech]

Logging Bluetooth packets shows that the OS is issuing a Read By Type request starting with handle 0x0002. No reply to this is ever received from the hub. I'm pretty sure other OSes (and previous versions of macOS?) issue this command starting with handle 0x0001, so we probably need to look at the Bluetooth driver in pbdrv to make sure it works for this case.

[dlech]

Reading the screenshot a bit closer, we can see this is actually requesting the Device Name UUID rather than the expected GATT Characteristic UUID.