Fix unstructured logging variable formatting #4497

Job	Run time
build (_delphi_utils_python, delphi_utils)	1m 49s
build (changehc, delphi_changehc)	1m 35s
build (claims_hosp, delphi_claims_hosp)	1m 43s
build (doctor_visits, delphi_doctor_visits)	1m 25s
build (google_symptoms, delphi_google_symptoms)	2m 5s
build (hhs_hosp, delphi_hhs)	1m 12s
build (nchs_mortality, delphi_nchs_mortality)	2m 5s
build (nssp, delphi_nssp)	1m 8s
build (nwss_wastewater, delphi_nwss)	1m 19s
build (quidel_covidtest, delphi_quidel_covidtest)	1m 23s
build (sir_complainsalot, delphi_sir_complainsalot)	1m 23s
	17m 7s

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