Scan from ScanController instead of GattService

See go/scan-manager-refactor for more details.

Test: m com.android.btservices
Test: Manual. Start a BluetoothLeScanner and scan for nearby devices. With the flag enabled, the new ScanController will be used
Bug: 313335632
Bug: 267361243
Bug: 327503826
Change-Id: I10bad9a78620c1ccb621b96961d217baf3d4e440