Add Loud Sound Reduction toggle

AirPods Pro 2nd gen and 3rd gen have an on/off toggle for "Loud Sound Reduction" on iOS.

This feature tries to reduce loud environment sound over ~85 dB(A) in Transparency & Adaptive Transparency modes by lowering transparency passthrough volume and/or using ANC in real-time, as far as I know.

Since the introduction of this Loud Sound Reduction feature, Apple has introduced ["Hearing Protection" feature](https://support.apple.com/en-us/120850) on AirPods, which I believe is the same feature, just allowed to be called as hearing protection in certain countries, but don't trust me on that. AirPods Pro 3rd gen probably have more allowed countries for that, see https://regulatoryinfo.apple.com/hearingprotection.

Ideally I'd say the toggle should warn the user when trying to disable it to make sure they're aware this reduces only environment sound because I can imagine users turning this off to get "max headphone volume" without knowing what it does. But that's just a bonus I guess :)

No files, tests, or entry points are named. Start by locating the existing AirPods Pro Transparency and Adaptive Transparency controls and the Bluetooth protocol handling, then compare Loud Sound Reduction or Hearing Protection support for AirPods Pro 2 and 3; done means an on/off toggle works in those modes.

Written by the indexing model from the issue text.