NIFI-15840 Added rollback in ExecuteGroovyScript to allow script access to FlowFile.

[dan-s1]

Summary

NIFI-15840
This PR fixes the bug in ExecuteGroovyScript so it should not fail with "Failure Strategy = transfer to failure" when there is a Groovy script that accesses a FlowFile.
In addition to this fix, this PR resolved some of the Intellij warnings.

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  • JDK 21
  • JDK 25

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[pvillard31]

I do not believe this is correct/enough. Consider this test where it fails before we do the get in the script:

@Test
void testTransferToFailureStrategyWhereScriptFailsBeforeGet() {
    runner.setProperty(ExecuteGroovyScript.SCRIPT_BODY, """
            throw new RuntimeException("fail before get")
            """);
    runner.setProperty(ExecuteGroovyScript.FAIL_STRATEGY, ExecuteGroovyScript.TRANSFER_TO_FAILURE);
    runner.assertValid();
    runner.enqueue("test content".getBytes(StandardCharsets.UTF_8));
    runner.run();
    runner.assertAllFlowFilesTransferred(ExecuteGroovyScript.REL_FAILURE, 1);
}

[pvillard31]

Latest LGTM, thanks @dan-s1