CDRIVER-4635 Reset speculative_auth_response when resetting auth state (#1258)

* CDRIVER-4635 add regression test

* reset authentication state before creating stream

* remove unnecessary state reset in `mongoc_topology_scanner_node_disconnect`

`mongoc_topology_scanner_node_disconnect` sets `stream` to NULL. That will result in the stream being recreated and state being reset in `mongoc_topology_scanner_node_setup`

* skip `/Client/authenticate_cached/client` when using speculativeAuthentication

This previously passed because SCRAM would fail speculativeAuthentication and restart the authentication steps. The restart would use the SCRAM cache.

Now speculativeAuthentication succeeds. speculativeAuthentication in the topology scanner does not use the SCRAM cache (refer: CDRIVER-3642). This does not result in the expected error.

* Reset scram step along with speculative authentication

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Co-authored-by: Kevin Albertson <kevin.albertson@mongodb.com>