refactor: fix `nullCoalesce.variable` errors #13137

Job	Run time
Setup PHP Version for Code Coverage	7s
Others (8.4) / Sanity Tests	2m 22s
Others (8.2) / Sanity Tests	3m 23s
Others (8.3) / Sanity Tests	2m 37s
Others (8.1) / Sanity Tests	3m 17s
CacheLive	0s
SeparateProcess	0s
Upload coverage results to Coveralls	0s
DatabaseLive	0s
	11m 46s

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