isMicrophoneAvailable is not working as docs suggest.

[maariyadiminsky]

@JamesBrill According to the docs this should be false if the user does not give permission but it is still true.

To reproduce:

• Give permission.
• Later remove permission and reload.
• isMicrophoneAvailable will be true.

[theisof]

I got the same problem so created this hook to get the permission state via the Permissions API. Feel free to use it.