fix: nil pointer dereference on item (#1290)

[Lin-1997]

Please provide issue(s) of this PR:
Fixes #1290

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[polaris-test-bot]

2023-11-22 18:12:10: =========TEST START==========
2023-11-22 19:08:16: [STANDALONE VERSION]PR autotest FAILED! We executed 40 test cases and 34 were passed. You can see test report in https://polaris-opentest-1306863770.cos.ap-guangzhou.myqcloud.com/pr1612499480/sta/qta-report.html and https://polaris-opentest-1306863770.cos.ap-guangzhou.myqcloud.com/pr1612499480/sta/ratelimit/qta-report.html
2023-11-22 19:08:21: [CLUSTER VERSION] PR autotest FAILED! We executed 39 test cases and 30 were passed. You can see test report in https://polaris-opentest-1306863770.cos.ap-guangzhou.myqcloud.com/pr1612499480/clu/qta-report.html
2023-11-22 19:08:24: [KUBENETES VERSION]PR autotest FAILED! We executed 39 test cases and 33 were passed. You can see test report in https://polaris-opentest-1306863770.cos.ap-guangzhou.myqcloud.com/pr1612499480/k8s/qta-report.html

[chuntaojun]

LGTM