deps: remove unused dependencies

[shekhirin]

❯ cargo machete
Analyzing dependencies of crates in this directory...
cargo-machete found the following unused dependencies in this directory:
reth-network-types -- ./crates/net/network-types/Cargo.toml:
        humantime-serde
reth-network-api -- ./crates/net/network-api/Cargo.toml:
        alloy-consensus
        alloy-rpc-types-eth
reth-stages-types -- ./crates/stages/types/Cargo.toml:
        modular-bitfield
reth-e2e-test-utils -- ./crates/e2e-test-utils/Cargo.toml:
        reth-engine-local
reth-era -- ./crates/era/Cargo.toml:
        ethereum_ssz
        ethereum_ssz_derive
reth-db-models -- ./crates/storage/db-models/Cargo.toml:
        modular-bitfield
reth-db-api -- ./crates/storage/db-api/Cargo.toml:
        modular-bitfield
reth-prune-types -- ./crates/prune/types/Cargo.toml:
        modular-bitfield
reth-primitives-traits -- ./crates/primitives-traits/Cargo.toml:
        modular-bitfield
        secp256k1
remote-exex -- ./docs/vocs/docs/snippets/sources/exex/remote/Cargo.toml:
        prost
exex-subscription -- ./examples/exex-subscription/Cargo.toml:
        clap
example-custom-node -- ./examples/custom-node/Cargo.toml:
        modular-bitfield

Some of these were actually false positives