CCodecBufferChannel: decrease balance for discarded work as well

Bug: 367371849
Test: atest MctsMediaEncoderTestCases
(cherry picked from https://android-review.googlesource.com/q/commit:9dbb416f7dcf3ef0f27af769fc6524c6d9716320)
Merged-In: I482c2a731f95b7f8e9c3e4ed4ce7ac4d0aae94df
Change-Id: I482c2a731f95b7f8e9c3e4ed4ce7ac4d0aae94df
1 file changed