fix(core): Add missing dedupe operation logic

[kitten]

Summary

This adds the missing logic that handles deduplication before a response has come back for a query or subscription operation. While we already ported logic from the dedupExchange to the Client that disallowed sending new operations for operations that currently have a hasNext flag set or are active, we now also take care of dispatched operations that haven't received a response yet.

The tests validate that the behaviour is equivalent to before and that operations are dispatched when reexecuteOperation is called, since those are on a delay, so that reexecutions can come through, for requestPolicy upgrades (e.g. for cache-and-network)

Set of changes

• Add missing teardown and dispatched checks to Client for dedupExchange replacement logic

[JoviDeCroock]

Should we make the dedupExchange a noop?