Prevent audioflinger battery notes leak

Ensure battery notes from audioflinger are encapsulated in an RAII
object so noteStart is always properly matched.

Remove uid refcounting in audioserver, since it already exists in
the battery notifier utility class, and is error-prone. As a byproduct,
notes occur during track transitions rather than in the threadloop,
which happens to avoid problematic blocking.

Bump refcount mismatch logging to error.

Bug: 259449389
Test: Manual verification of battery stats notes w/ multiple refs
Change-Id: Ifc931a9ac46f37d662e42dd4696f0a62eec22c25