KAFKA-18171: Unexpected Change in bootstrap.servers Behavior After Upgrade to 3.8.0

[pranavt84]

JIRA: KAFKA-18171

*This PR check *

*With this change, bootstrap.servers property now will support values that is separated by space or new line or comma followed by new line.
We can specify values for bootstrap.servers like below-

1. "broker1:port1 broker2:port2 broker3:port3"
2. "broker1:port1,broker2:port2,broker3:port3"
3. "broker1:port1, broker2:port2, broker3:port3"

"broker1:port1,
broker2:port2,
broker3:port3"

Committer Checklist (excluded from commit message)

• Verify design and implementation
• Verify test coverage and CI build status
• Verify documentation (including upgrade notes)

[chia7712]

I have left a comment on the jira. copy to here:

according to kafka docs: "This list must be in the form <code>host1:port1,host2:port2,...</code>." https://github.com/apache/kafka/blob/be7415cb8bf5e09ad969cccfcbffd30fd68804ea/clients/src/main/java/org/apache/kafka/clients/CommonClientConfigs.java#L51

Hence, I'm not sure whether this is a kind of bug.

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