chore: remove legacy `rnpm` config #2558

Job	Run time
diff_check / diff_check	8s
cancel-previous-workflow	3s
Build legacy android dev no-frameworks	4m 29s
Build legacy android production no-frameworks	5m 59s
Build legacy ios dev no-frameworks	17m 36s
Build legacy ios production no-frameworks	19m 20s
Build legacy macos dev no-frameworks	13m 31s
Build legacy macos production no-frameworks	15m 50s
Build legacy ios dev dynamic-frameworks	14m 54s
Build legacy ios production dynamic-frameworks	18m 5s
Build new android dev no-frameworks	4m 12s
Build new android production no-frameworks	5m 47s
Build new ios dev no-frameworks	17m 40s
Build new ios production no-frameworks	17m 52s
	2h 35m 26s

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