Bump `getrandom` to v0.4.0-rc.1 #3915

Job	Run time
test-careful	1m 3s
build (stable, thumbv7em-none-eabi)	48s
test-miri	48s
build (1.85.0, thumbv7em-none-eabi)	47s
build (1.85.0, wasm32-unknown-unknown)	40s
test (1.85.0)	35s
test (nightly)	32s
test (stable)	32s
build (stable, wasm32-unknown-unknown)	43s
minimal-versions	-1s
	6m 27s

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