fix(validation): Calculate counterparty balance from channel state #5149

Job	Run time
lint-commits	4s
formatting-dprint	18s
generate-ffi	3m 45s
ln-dlc-node-tests	4m 25s
e2e_tests_prepare	8m 55s
payout-curve	2m 1s
clippy	3m 57s
Format and lint Flutter code	42s
unit-tests	4m 39s
e2e-tests (./target/debug/deps/e2e_basic-062ad8b29bc5fb67)	2m 14s
e2e-tests (./target/debug/deps/e2e_close_position-3dded1c289c7c1e1)	3m 4s
e2e-tests (./target/debug/deps/e2e_collaborative_close_channel-89a5b0e4038168d6)	3m 17s
e2e-tests (./target/debug/deps/e2e_collaborative_revert-a80c38b7a6859606)	3m 10s
e2e-tests (./target/debug/deps/e2e_force_close_position-327c4e007e28193e)	3m 14s
e2e-tests (./target/debug/deps/e2e_open_position-cd45a55b17e2b350)	2m 24s
e2e-tests (./target/debug/deps/e2e_open_position_small_utxos-7198bf953c6f9db3)	3m 47s
e2e-tests (./target/debug/deps/e2e_reject_offer-f00708b7bba3393c)	2m 10s
e2e-tests (./target/debug/deps/e2e_restore_from_backup-1e94385a148ef84a)	3m 16s
e2e-tests (./target/debug/deps/e2e_rollover_position-721d353c6d05d131)	2m 43s
e2e_tests_check	1s
	58m 6s

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