Speedup leaf_hash in data_layer_util.py

[AmineKhaldi]

Making it also type safe as a result.

[emlowe]

Close and reopen for benchmarks fix

[coveralls-official]

Pull Request Test Coverage Report for Build 8380938680

Details

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• 16 unchanged lines in 8 files lost coverage.
• Overall coverage increased (+0.01%) to 90.834%

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Files with Coverage Reduction	New Missed Lines	%
chia/rpc/rpc_server.py	1	88.67%
chia/_tests/core/util/test_lockfile.py	1	91.09%
chia/server/node_discovery.py	1	79.96%
chia/rpc/wallet_rpc_api.py	1	89.2%
chia/introducer/introducer.py	1	78.26%
chia/wallet/wallet_node.py	2	88.56%
chia/server/server.py	4	80.0%
chia/introducer/introducer_api.py	5	78.26%

Totals
Change from base Build 8378992295:	0.01%
Covered Lines:	97426
Relevant Lines:	107233

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💛 - Coveralls