filter_log_to_metrics: Fix config key after rename #8054

Job	Run time
run-ubuntu-unit-tests (-DFLB_JEMALLOC=On, gcc)	19m 23s
run-ubuntu-unit-tests (-DFLB_JEMALLOC=On, clang)	18m 59s
run-ubuntu-unit-tests (-DFLB_JEMALLOC=Off, gcc)	18m 7s
run-ubuntu-unit-tests (-DFLB_JEMALLOC=Off, clang)	17m 39s
run-ubuntu-unit-tests (-DFLB_SMALL=On, gcc)	18m 19s
run-ubuntu-unit-tests (-DFLB_SMALL=On, clang)	19m 8s
run-ubuntu-unit-tests (-DSANITIZE_ADDRESS=On, gcc)	18m 26s
run-ubuntu-unit-tests (-DSANITIZE_ADDRESS=On, clang)	18m 39s
run-ubuntu-unit-tests (-DSANITIZE_UNDEFINED=On, gcc)	18m 38s
run-ubuntu-unit-tests (-DSANITIZE_UNDEFINED=On, clang)	18m 11s
run-ubuntu-unit-tests (-DFLB_COVERAGE=On, gcc)	50m 58s
run-ubuntu-unit-tests (-DFLB_SANITIZE_MEMORY=On, gcc)	18m 0s
run-ubuntu-unit-tests (-DFLB_SANITIZE_MEMORY=On, clang)	17m 50s
run-ubuntu-unit-tests (-DFLB_SANITIZE_THREAD=On, gcc)	19m 3s
run-ubuntu-unit-tests (-DFLB_SANITIZE_THREAD=On, clang)	18m 33s
run-macos-unit-tests (-DFLB_JEMALLOC=Off)	13m 37s
run-macos-unit-tests (-DFLB_SANITIZE_MEMORY=On)	13m 55s
run-macos-unit-tests (-DFLB_SANITIZE_THREAD=On)	14m 1s
Unit tests (matrix)	1s
	5h 51m 27s

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