Duplicate header processing in `BatchMessagingMessageConverter#processRecord()`

[borahm-lee]

In what version(s) of Spring for Apache Kafka are you seeing this issue?

For example:

• 3.3.0-SNAPSHOT

Describe the bug

• Originally, logs were supposed to be left once per record list when there is no headerMapper, but now they are left as many times as there are records.
• Similarly, putting listenerInfo on rawHeaders is being attempted as many times as there are records.

To Reproduce

• Run BatchMessageConverterTests#testNoMapper().

Expected behavior

• It only logs once when there is no headerMapper.
• Putting listenerInfo to rawHeaders is also attempted only once.

Sample

Currently, the logs in the code are at the DEBUG level, but I changed them to WARN for ease of reading.

• Test before fixing:
  

• Test after fixing:
  

I'm opening a PR right away to address this issue.

[sobychacko]

PR merged.