Although it's the caller's duty to avoid WSClient re-closing, we
still can handle it.
Fixes the following neofs-node error:
```
panic: close of closed channel
goroutine 98 [running]:
github.com/nspcc-dev/neo-go/pkg/rpc/client.(*WSClient).Close(...)
github.com/nspcc-dev/neo-go@v0.98.3-pre.0.20220321144433-3b639f518ebb/pkg/rpc/client/wsclient.go:120
github.com/nspcc-dev/neofs-node/pkg/morph/subscriber.(*subscriber).Close(0x13)
github.com/nspcc-dev/neofs-node/pkg/morph/subscriber/subscriber.go:108 +0x29
github.com/nspcc-dev/neofs-node/pkg/morph/event.listener.Stop(...)
github.com/nspcc-dev/neofs-node/pkg/morph/event/listener.go:573
created by github.com/nspcc-dev/neofs-node/pkg/innerring.(*Server).Stop
github.com/nspcc-dev/neofs-node/pkg/innerring/innerring.go:285 +0x12f
```
1. Keep initDone check only for the places where cache is directly accessed.
We don't need to check it in other places, otherwise we have a mess of
duplicating checks.
2. Fix bug in code related to block deserialisation. There's no magic, so
checking that initialisation is done is not enough for proper block
deserialisation. We need to manually fill StateRootEnabled field.
3. Since transaction doesn't need network magic to compute its hash, we don't
need to perform Client initialisation before transaction-related requests.
4. Check that cache is initialised before accessing network magic.
5. Refactor the way Policy contract hash is fetched for Client requests.
We don't really need Client initialisation for that, it's OK to fetch Policy
hash on-the-fly.
We make it explicit in the appropriate Block/Transaction structures, not via a
singleton as C# node does. I think this approach has a bit more potential and
allows better packages reuse for different purposes.
It doesn't affect anything yet, but it's going to be used in the future for
network-specific behavior. It also renames short '--timeout' form to '-s'
avoiding conlict with '-t' used for '--testnet'.
Two changes being done here, because they require a lot of updates to
tests. Now we're back into version 0 and we only have one type of
transaction.
It also removes GetType and GetScript interops, both are obsolete in Neo 3.
Our block.Block was JSONized in a bit different fashion than result.Block in
its NextConsensus and Index fields. It's not good for notifications because
third-party clients would probably expect to see the same format. Also, using
completely different Block representation is probably making our client a bit
weaker as this representation is harder to use with other neo-go components.
So use the same approach we took for Transactions and wrap block.Block which is
to be serialized in proper way.
Fix `Script` JSONization along the way, 3.0 node wraps it within `witnesses`.
