floss: Add IsLEAudioSupported API

Add new API IsLEAudioSupported that checks controller CIS Central
support from LEReadLocalSupportedFeatures. This mirrors Linux's
implementation.

Bug: 257881495
Tag: #floss
Test: btclient - adapter show
Test: mmm packages/modules/Bluetooth
Flag: EXEMPT, floss change for ChromeOS only
Change-Id: I44844a924398c02c907752f7ab4e4c843a220818