fix(sdk): reuse Channel in NetworkClient #7823

Job	Run time
Examples	6m 8s
Test (x86-64)	42m 15s
Test (ARM)	31m 15s
Formatting & Clippy	6m 6s
Cargo Check (Nightly)	7m 10s
Test Verifier Crate	39m 6s
Cargo Check	6m 55s
Check Verifier `no_std`	27s
Check lock files	6m 25s
Build patches and zkvm in host	1m 10s
	2h 26m 57s

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