Update collect_dast_scan_crawl_metrics_from_pipeline label

What does this MR do and why?

Update collect_dast_scan_crawl_metrics_from_pipeline event definition to correct label field description, this feild captures the total crawl time in milliseconds.

References

Update collect_dast_scan_crawl_metrics_from_pip... (#583973 - closed) • Hannah Baker • 18.8

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Related to #583973 (closed)