Update arguments of BluetoothStatsLog.write for scan and adv metrics with empty value

The new argument is needed due to the new field being added to the scan and adv atoms.
The empty value will be replaced with acutal value in a separate change.

Bug: 389731079
Flag: EXEMPT, metrics update
Test: atest ScanManagerTest AppAdvertiseStatsTest
Ignore-AOSP-First: workflow for modifying existing atoms
Change-Id: I8012579276522dd42f409ec4c8a2a0f48190772b