Fix statsd ble scan logging

Ble scan logging in statsd has a few problems:

1. We want finer-grained detailed than just 'unoptimized'. What defines
unoptimized should be done at the config level, not be hard-coded.

2. The current mechanism is actually incorrect. When reset is called,
each ble scan is only told *once* that it stopped, but if the nesting
level is higher than that, statsd will think it is still nonetheless
running.

Test: cts-tradefed run cts-dev -m CtsStatsdHostTestCases -t android.cts.statsd.atom.UidAtomTests#testBleUnoptimizedScan
Test: cts-tradefed run cts-dev -m CtsStatsdHostTestCases -t android.cts.statsd.atom.UidAtomTests#testBleScan
Fixes: 71607284
Fixes: 69478888

Change-Id: Ied44f79aa569daab2acc85e90627a9736d0689a3