Add rms_norm op (#19893) #3

Job	Run time
test-webgpu / test-backend-linux (webgpu, models) / linux-job	8m 0s
test-webgpu / test-backend-linux (webgpu, operators) / linux-job	8m 5s
test-webgpu / test-backend-macos	-1s
test-webgpu / package-golden-artifacts	0s
	16m 4s

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