Also clear the foreground service usage time for BatteryDiffEntry should hide background usage time.

- Usage time in background is the sum{bg + fgs} usage time

Bug: 371919020
Fix: 371919020
Test: atest DataProcessorTest
Flag: EXEMPT for simple fix
Change-Id: I058d8511eac7510e2df6d9ac1713824cd8dbf3ba
2 files changed