dashboard/app: add spanner Jobs.Correct field #18746

Job	Run time
race_dashboard	2m 38s
build	3m 16s
race	7m 19s
aux	4m 10s
old	7m 3s
arch (presubmit_arch_darwin)	3m 46s
arch (presubmit_arch_freebsd)	6m 7s
arch (presubmit_arch_netbsd)	3m 58s
gvisor	4m 10s
arch (presubmit_arch_linux)	11m 30s
arch (presubmit_arch_executor)	3m 19s
arch (presubmit_arch_windows)	3m 35s
arch (presubmit_arch_openbsd)	3m 50s
dashboard	2m 38s
	1h 7m 19s

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