Fix KafkaAppender reporting error after successful retry

[SebTardif]

Fix KafkaAppender retry logic that always reports an error to the error handler even when a retry succeeds.

When retryCount is configured and the initial tryAppend() fails, the retry loop uses break to exit on success. However, break only exits the while loop; execution always reaches the error() call afterward. This causes spurious error notifications for transient Kafka failures that were successfully recovered by a retry.

This change replaces break with return so that a successful retry exits append() without reporting an error. Retry exceptions are now logged at DEBUG level for diagnostics instead of being silently discarded.

Also removes dead code in Builder.getRetryCount() where Integer.valueOf(int) was wrapped in a NumberFormatException catch that can never fire.

The bug was introduced in #315.

Checklist

• Base your changes on 2.x branch if you are targeting Log4j 2; use main otherwise
• ./mvnw verify succeeds (the build instructions)
• Tests are provided

[ramanathan1504]

LGTM overall — great fix for the break/return retry behavior, and thanks for adding DEBUG logging plus cleaning up getRetryCount().

One small suggestion commented to keep the diff minimal: retain the existing while loop shape and just apply the early return + DEBUG logging inside it.

[ramanathan1504]

if (this.retryCount != null) {
                    int currentRetryAttempt = 0;
                    while (currentRetryAttempt < this.retryCount) {
                        currentRetryAttempt++;
                        try {
                            tryAppend(event);
                            return; // Fix: Exit early on success
                        } catch (final Exception retryException) {
                            LOGGER.debug(
                                    "Unable to write to Kafka in appender [{}], retry attempt [{}/{}].",
                                    getName(),
                                    currentRetryAttempt,
                                    this.retryCount,
                                    retryException);
                        }
                    }
                }

This still applies all three of your excellent fixes (early return, no swallowed exceptions, and preserving the stack trace in debug mode) but modifies fewer lines of code.