kona|op-devstack: Revise Sequencer detection while test bootstrapping

[pcw109550]

Found while attempting to run monorepo acceptance tests targeting kona-node.

op-devstack spins up preset network, and detect whether the L2 CL Node is sequencer via calling the admin_sequencerActive() API.

optimism/op-devstack/stack/match/sequencer.go

Lines 10 to 21 in 903584f

	func WithSequencerActive(ctx context.Context) stack.Matcher[stack.L2CLNodeID, stack.L2CLNode] {
	return MatchElemFn[stack.L2CLNodeID, stack.L2CLNode](func(elem stack.L2CLNode) bool {
	sequencing, err := retry.Do(ctx, 10, retry.Exponential(), func() (bool, error) {
	return elem.RollupAPI().SequencerActive(ctx)
	})
	if err != nil {
	// Not available so can't be used by the test
	return false
	}
	return sequencing
	})
	}

This means kona node must be always admin API enabled. Need to patch op-devstack/sysgo/l2_cl_kona.go and add "KONA_NODE_RPC_ENABLE_ADMIN=true". Or we may patch the devstack to not use the admin API for sequencer detection.

Even after this fix, we may need kona-node patch at https://github.com/op-rs/kona/blob/fe6dfcf771059109f1d75043d5ecbbfa3b6ca1a5/crates/node/rpc/src/admin.rs#L95-L99.

This behavior is inconsistent with op-node. If admin API enabled but validator, we must not return ErrorCode::MethodNotFound