out_azure_logs_ingestion: fix NULL dereference (#7624) #8021

Job	Run time
run-ubuntu-unit-tests (-DFLB_JEMALLOC=On, gcc)	19m 41s
run-ubuntu-unit-tests (-DFLB_JEMALLOC=On, clang)	18m 42s
run-ubuntu-unit-tests (-DFLB_JEMALLOC=Off, gcc)	18m 4s
run-ubuntu-unit-tests (-DFLB_JEMALLOC=Off, clang)	18m 50s
run-ubuntu-unit-tests (-DFLB_SMALL=On, gcc)	18m 19s
run-ubuntu-unit-tests (-DFLB_SMALL=On, clang)	20m 14s
run-ubuntu-unit-tests (-DSANITIZE_ADDRESS=On, gcc)	18m 38s
run-ubuntu-unit-tests (-DSANITIZE_ADDRESS=On, clang)	18m 2s
run-ubuntu-unit-tests (-DSANITIZE_UNDEFINED=On, gcc)	20m 1s
run-ubuntu-unit-tests (-DSANITIZE_UNDEFINED=On, clang)	18m 11s
run-ubuntu-unit-tests (-DFLB_COVERAGE=On, gcc)	18m 46s
run-ubuntu-unit-tests (-DFLB_SANITIZE_MEMORY=On, gcc)	18m 24s
run-ubuntu-unit-tests (-DFLB_SANITIZE_MEMORY=On, clang)	17m 56s
run-ubuntu-unit-tests (-DFLB_SANITIZE_THREAD=On, gcc)	19m 3s
run-ubuntu-unit-tests (-DFLB_SANITIZE_THREAD=On, clang)	18m 47s
run-macos-unit-tests	0s
Unit tests (matrix)	2s
	4h 41m 40s

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