fix get kserve job panic

[gujingit]

/kind bugfix

Run command serve get qwen --type kserve

Output errors:

报错内容：goroutine 1 [running]:
github.com/kubeflow/arena/pkg/serving.(*servingJob).GetLabels(...)
        /Users/baizi/Documents/code/src/github.com/kubeflow/arena/pkg/serving/serving.go:321
github.com/kubeflow/arena/pkg/apis/arenaclient.(*ServingJobClient).GetAndPrint(0x14000c8fbc0, {0x16efeb584, 0x4}, {0x0, 0x0}, {0x10263e759, 0x6}, {0x10263c896, 0x4})
        /Users/baizi/Documents/code/src/github.com/kubeflow/arena/pkg/apis/arenaclient/serving_client.go:90 +0x310
github.com/kubeflow/arena/pkg/commands/serving.NewGetCommand.func2(0x1400029c800?, {0x14000983bf0?, 0x4?, 0x10263c8c2?})
        /Users/baizi/Documents/code/src/github.com/kubeflow/arena/pkg/commands/serving/get.go:60 +0x244
github.com/kubeflow/arena/vendor/github.com/spf13/cobra.(*Command).execute(0x140008da008, {0x14000983b90, 0x3, 0x3})
        /Users/baizi/Documents/code/src/github.com/kubeflow/arena/vendor/github.com/spf13/cobra/command.go:940 +0x654
github.com/kubeflow/arena/vendor/github.com/spf13/cobra.(*Command).ExecuteC(0x14000434c08)
        /Users/baizi/Documents/code/src/github.com/kubeflow/arena/vendor/github.com/spf13/cobra/command.go:1068 +0x320
github.com/kubeflow/arena/vendor/github.com/spf13/cobra.(*Command).Execute(0x1400008c6f8?)
        /Users/baizi/Documents/code/src/github.com/kubeflow/arena/vendor/github.com/spf13/cobra/command.go:992 +0x1c
main.main()
        /Users/baizi/Documents/code/src/github.com/kubeflow/arena/cmd/arena/main.go:63 +0x300

[google-oss-prow[bot]]

@gujingit: The label(s) kind/, kind/bugfix cannot be applied, because the repository doesn't have them.

In response to [this](https://github.com/kubeflow/arena/pull/1085): >/kind bugfix > >Run command `serve get qwen --type kserve` > >Output errors: >``` >报错内容：goroutine 1 [running]: >github.com/kubeflow/arena/pkg/serving.(*servingJob).GetLabels(...) > /Users/baizi/Documents/code/src/github.com/kubeflow/arena/pkg/serving/serving.go:321 >github.com/kubeflow/arena/pkg/apis/arenaclient.(*ServingJobClient).GetAndPrint(0x14000c8fbc0, {0x16efeb584, 0x4}, {0x0, 0x0}, {0x10263e759, 0x6}, {0x10263c896, 0x4}) > /Users/baizi/Documents/code/src/github.com/kubeflow/arena/pkg/apis/arenaclient/serving_client.go:90 +0x310 >github.com/kubeflow/arena/pkg/commands/serving.NewGetCommand.func2(0x1400029c800?, {0x14000983bf0?, 0x4?, 0x10263c8c2?}) > /Users/baizi/Documents/code/src/github.com/kubeflow/arena/pkg/commands/serving/get.go:60 +0x244 >github.com/kubeflow/arena/vendor/github.com/spf13/cobra.(*Command).execute(0x140008da008, {0x14000983b90, 0x3, 0x3}) > /Users/baizi/Documents/code/src/github.com/kubeflow/arena/vendor/github.com/spf13/cobra/command.go:940 +0x654 >github.com/kubeflow/arena/vendor/github.com/spf13/cobra.(*Command).ExecuteC(0x14000434c08) > /Users/baizi/Documents/code/src/github.com/kubeflow/arena/vendor/github.com/spf13/cobra/command.go:1068 +0x320 >github.com/kubeflow/arena/vendor/github.com/spf13/cobra.(*Command).Execute(0x1400008c6f8?) > /Users/baizi/Documents/code/src/github.com/kubeflow/arena/vendor/github.com/spf13/cobra/command.go:992 +0x1c >main.main() > /Users/baizi/Documents/code/src/github.com/kubeflow/arena/cmd/arena/main.go:63 +0x300 >``` Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes-sigs/prow](https://github.com/kubernetes-sigs/prow/issues/new?title=Prow%20issue:) repository.

[google-oss-prow[bot]]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: Once this PR has been reviewed and has the lgtm label, please ask for approval from gujingit. For more information see the Kubernetes Code Review Process.

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files: - **[OWNERS](https://github.com/kubeflow/arena/blob/master/OWNERS)** Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment