Update pallet nomination pool to support Block Number Provider #15455

Job	Run time
preflight / preflight	42s
preflight / ci-versions	59s
test-linux-stable-runtime-benchmarks	31m 32s
test-linux-stable-int	10m 27s
test-linux-stable-no-try-runtime (1/2)	40m 31s
test-linux-stable (1/3, parity-large)	43m 9s
test-linux-stable-no-try-runtime (2/2)	32m 16s
test-linux-stable (1/3, parity-oldlinux)	36m 19s
test-linux-stable (2/3, parity-large)	31m 24s
test-linux-stable (2/3, parity-oldlinux)	20m 54s
test-linux-stable (3/3, parity-large)	30m 53s
test-linux-stable (3/3, parity-oldlinux)	20m 15s
All tests passed	1s
	4h 59m 22s

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