floss: changes data type of PHY for advertising to LePhy

This patch moves LePhy definition from stack to bt_btif::profiles::gatt
so that BLE advertising can align its PHY type to other interfaces.

Bug: 237346241
Tag: #floss
Test: build.py --target test
Test: `bclient advertise on` and check their type on dbus-monitor
Change-Id: I1514aa73cc4a337e22921df03347dea6e24b5d79