Log the excessive incoming binder proxies into statsd

This CL introduces a new "warning" callback on excessive binder
proxies, where if the total count of binder proxies from certain UID
goes above the threshold, the callback will be triggered. This is
very similar to the existing binder proxy high watermark callback.

We're logging this warning event into statsd, where it may trigger
perfetto dump, before it reaches to the high watermark and gets killed
because of that.

This callback signal could also be used as a hint to the GC in
the future, which could effectively release the references to
remote binder stubs.

(cherry-picked from ag/25078745)

Flag: ACONFIG log_excessive_binder_proxies DEVELOPMENT
Bug: 298263955
Test: atest FrameworksCoreTests:android.os.BinderProxyCountingTest
Merged-In: I3c959a7dd62ee57415c22a8034d774fe49a8f64f
Change-Id: I2eac629a1a63877adc432b23aae36d83a93c538e