test(firebase): fix tests on low API levels #391

Job	Run time
Run lint on project	4m 53s
Build job	5m 33s
Run common tests on Firebase	2m 52s
Run emarsys tests on Firebase	4m 28s
Create release bundle	4m 56s
Run core tests on Firebase	2m 40s
Run emarsys-firebase tests on Firebase	2m 40s
Run emarsys-huawei tests on Firebase	2m 53s
Run emarsys-sdk tests on Firebase	2m 48s
Run mobile-engage tests on Firebase	2m 52s
Run predict tests on Firebase	2m 48s
Release sample app	0s
Send slack on error	4s
Send slack notification	0s
	39m 27s

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