fix: adjust minJavaVersion to 17 and fix compile warnings (#2717)

[QianChenJun]

Fixes #2717
Changes

• Updated minJavaVersion from 11 to 17.

Reason

• The code uses APIs introduced in Java 13 and above, which caused errors with the previous version setting.
• Java 17 is an LTS release that ensures better long-term support and aligns with Kafka ecosystem recommendations.

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Summary of testing strategy (including rationale)
for the feature or bug fix. Unit and/or integration
tests are expected for any behaviour change and
system tests should be considered for larger changes.

Committer Checklist (excluded from commit message)

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

[CLAassistant]

All committers have signed the CLA.

[Gezi-lzq]

Thank you for your contribution. While reviewing the CI status, I noticed that if we directly change the JDK version to 17, some APIs in the client and other dependent modules would be marked as deprecated, causing the CI to fail.
In the Apache Kafka community, there is a similar change: apache/kafka#17522, which supports this by distinguishing the minimum JDK versions supported by different modules.
Since this involves how to follow the changes in build.gradle made by Apache Kafka, the goal of this issue may need to be adjusted. I will sync this through comments later.