[SPARK-54098] Set --sun-misc-unsafe-memory-access=allow for JavaExec Gradle tasks

[dongjoon-hyun]

What changes were proposed in this pull request?

This PR aims to set --sun-misc-unsafe-memory-access=allow JVM option for JavaExec-type Gradle tasks.

Why are the changes needed?

To suppress the following JVM warning messages

> Task :spark-operator-api:compileJava
WARNING: A terminally deprecated method in sun.misc.Unsafe has been called
WARNING: sun.misc.Unsafe::objectFieldOffset has been called by lombok.permit.Permit
WARNING: Please consider reporting this to the maintainers of class lombok.permit.Permit
WARNING: sun.misc.Unsafe::objectFieldOffset will be removed in a future release

Does this PR introduce any user-facing change?

No behavior change.

How was this patch tested?

Pass the CIs and manually check.

$ gradle spark-operator-api:compileJava
Starting a Gradle Daemon, 4 stopped Daemons could not be reused, use --status for details

> Configure project :spark-operator-api
Updating PrinterColumns for generated CRD
WARNING: A terminally deprecated method in sun.misc.Unsafe has been called
WARNING: sun.misc.Unsafe::objectFieldOffset has been called by lombok.permit.Permit
WARNING: Please consider reporting this to the maintainers of class lombok.permit.Permit
WARNING: sun.misc.Unsafe::objectFieldOffset will be removed in a future release
...

Was this patch authored or co-authored using generative AI tooling?

No.