Fix audio mute by dtmf frames

When the dtmf payload is processed in the AudioRtpPayloadDecoder,
unexpected CMR operation makes audio codec error. I add statement to
prevent the dtmf payload processed in AudioPayloadDecoder.
Add statement for error filtering for zero payload in
RtpDecoder/RtpEncoderNode.

Bug: 260996850
Test: test with device with dtmf receiving case, atest ImsMediaNativeTests

Change-Id: I41db2fa4d12c7b7bca3542b5746c9e4aac78cfec
2 files changed