LCB metrics issue toward server 7

Scope :
Integration of libcouchbase 3.3.1 in Amadeus Proxy (An Amadeus component for mutualising connections).

Issue :
Incompatibility between libcouchbase  3.3.1 and Couchbase Server 7.0.3 while collecting the stats.

Description :

We encoutered a behavior change when the tests are being run on a Couchbase server 6.6.2 and a 7.0.3 server.
In fact , on 7.0.3 server , the number of stats that we are having is 3 Times the number of stats that we should have.

When using this method for retrieving metrics:
lcb_METRICS *lcb_metrics ;
lcb_cntl(sp->couchbase_client, LCB_CNTL_GET, LCB_CNTL_METRICS,
                      &lcb_metrics);

The development was initiated by sergey with this change :
https://review.couchbase.org/c/libcouchbase/+/85763
Our test case is to send 48 requests , and we are retrieving the lcb metrics :

When we are plugged on a server 6 , we sent 48 requests and and the stats retrieved for requests/responses are correct (48).
However when we are plugged on a server 7 , we sent 48 requests and the stats retrieved for requests/responses are 144 .

Note :
With libcouchbase 3.0.6 we had the same issue when we are plugged on a server.