fix: resolve panic issue in pipeline controller caused by CustomRun

[l-qing]

fix #8561

When validating the optional workspace of the pipeline, encountering a CustomRun should not cause a panic, as this configuration will be validated again during the creation of the CustomRun.

Changes

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Release Notes

fix: resolve panic issue in pipeline controller caused by CustomRun

/kind bug

[l-qing]

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[l-qing]

/retest

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[afrittoli]

/lgtm