RootCanal: Increase the number of supported advertising sets to 16

As mandated by the android bluetooth requirements for controllers
of HCI version > 5.0:
https://source.android.com/docs/compatibility/14/android-14-cdd#743_bluetooth

Test: m root-canal
Bug: 275847929
Change-Id: I4b79afeef163bf2aacb3164eaaa53bb8a7229a85