[FAB-13095] fix UT flake RPC timeout
[FAB-13095] fix UT flake RPC timeout

Sometimes, 100ms isn't enough for the RPC call to reach
the server, and therefore the request times out before
it invokes the mock.

Increased the timeout to 1 second, and tested this
in CI for more than 1,000 iterations in
a custom CR: https://gerrit.hyperledger.org/r/#/c/28258/

Change-Id: I01976373dcb66f652016f8916c5c86027e21f0d4
Signed-off-by: yacovm <632344b5da9bd743456189af4db4b56472defb8c@il.ibm.com>

manish-sethi/fabric-sidedb,jimthematrix/fabric,binhn/fabric,stemlending/fabric,manish-sethi/fabric-sidedb,manish-sethi/fabric-sidedb,manish-sethi/fabric-sidedb,stemlending/fabric,stemlending/fabric,manish-sethi/fabric-sidedb,hyperledger/fabric,manish-sethi/fabric-sidedb,manish-sethi/fabric,binhn/fabric,stemlending/fabric,hyperledger/fabric,muralisrini/fabric,muralisrini/fabric,manish-sethi/fabric-sidedb,jimthematrix/fabric,muralisrini/fabric,manish-sethi/fabric,binhn/fabric