Check for null address before doing permission requirements check

If the address is null, then we do not need to enforce at all.

@SystemApi caller should not be able to pass null address due to the checks in the API.

Only setDeviceAddress(String address may accept a null

Bug: 189231649
Test: Manual test app; atest CtsBluetoothTestCases:android.bluetooth.cts.BluetoothLeScanTest#testBasicBleScan -- --abi arm64-v8a
Tag: #feature
Change-Id: I82f1effaa9259bfd2fe944fa45a8ed33b221b3aa