Remove mCallQualityMetrics[callId] after call

Since the callId may be reused for future calls, we remove the
CallQualityMetrics object and save it in the history (for debugging
purposes)

Bug: 134179966
Test: manual
Change-Id: Ifeac02e0866ffe28c11f9472d9e0ba3f94ed4c2b
(cherry picked from commit c610e30f)