Electrum: optimize merkle proof validation with batching #7091

Job	Run time
prepare	4s
Build & Test (1.63.0, --no-default-features --features miniscript/no-std,bdk_chain/hashbrown)	4m 42s
Build & Test (1.85.0, true, --all-features)	4m 0s
Check no_std	42s
Build & Test (1.63.0, --all-features)	5m 6s
Build & Test (1.75.0, --no-default-features --features miniscript/no-std,bdk_chain/hashbrown)	2m 21s
Build & Test (1.75.0, --all-features)	4m 21s
Check WASM	55s
Build & Test (1.85.0, true, --no-default-features --features miniscript/no-std,bdk_chain/hashbrown)	2m 9s
Rust fmt	13s
Rust clippy	1m 8s
Build & Test Examples (example_wallet_esplora_blocking)	57s
Build & Test Examples (example_wallet_electrum)	56s
Build & Test Examples (example_esplora)	52s
Build & Test Examples (example_electrum)	57s
Build & Test Examples (example_wallet_rpc)	49s
Build & Test Examples (example_wallet_esplora_async)	57s
Build & Test Examples (example_cli)	33s
Build & Test Examples (example_bitcoind_rpc_polling)	39s
	32m 21s

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