[KIP-848] Add test cases for new OffsetCommit and OffsetFetch Error Codes (confluentinc#5194)

* Add test cases for new OffsetCommit and OffsetFetch Error Codes
* Testcase for discarding the member epoch in a consumer group heartbeat response when leaving with an inflight HB

Author: pranavrth

CHANGELOG.md

@@ -38,14 +38,22 @@ librdkafka v2.12.0 is a feature release:
   Happening since 2.5.0. Since 2.10.1 unit tests are failing when run on
   big-endian architectures (#5183, @paravoid).
 
+### Consumer fixes
+  
+  * Issues: #5199
+  Fixed an issue where topic partition errors were not cleared after a successful
+  commit. Previously, a partition could retain a stale error state even though the
+  most recent commit succeeded, causing misleading error reporting. Now, successful
+  commits correctly clear the error state for the affected partitions
+  Happening since 2.4.0 (#4672).
+
 ### Producer fixes
 
 * Issues: #4627.
   Fix double free of headers in `rd_kafka_produceva` method in cases where the partition doesn't exist.
   Happening since 1.x (@blindspotbounty, #4628).
 
 
-
 # librdkafka v2.11.1
 
 librdkafka v2.11.1 is a maintenance release: