AAudio: Wait for read/write in metrics tests

AAudio metrics tests are not checking that data is fully consumed by the
audio endpoint after it is added.
This CL adds a check for frames read after frames are written.

Bug: 289745101
Test: atest MediaMetricsAtomTests
Change-Id: I249f05944502c2a1309d85a58ad866444d1a9b22
(cherry picked from commit 2c8d293389f3160eeddcb4315977d31cb224849b)
Merged-In: I249f05944502c2a1309d85a58ad866444d1a9b22