libbinder: Add ClientCounterCallbackImpl to LazyServiceRegistrar

This extra layer of indirection below ClientCounterCallback fixes a shared pointer ownership issue between LazyServiceRegistrar and ServiceManager. It also allows for implementation changes (like this one) without changing headers and breaking VNDK.

Bug: 170212632
Test: Manual (Went through reproduction steps in bug on rvc-dev)
Test: atest aidl_lazy_test
Change-Id: I4164a6d44e567c752726953e85aee0e91c6b525e
(cherry picked from commit e31d33a3)
Merged-In: I4164a6d44e567c752726953e85aee0e91c6b525e