chore(core): Bump sample app to React Native 0.84.1 #12764

Job	Run time
Ready-to-merge gate / Missing "ready-to-merge" label	3s
diff_check / diff_check	9s
detect-changes / Detect file changes	5s
Build new ios dev no-frameworks	6m 54s
Build new android dev	12m 5s
Build new ios production no-frameworks	6m 42s
Build legacy macos dev	5m 27s
Build legacy macos production	6m 7s
Build new android production	14m 20s
Test ios production REV2	3m 37s
Test android production REV2	0s
	55m 29s

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