Fix tests for driver_master

[johnnyshields]

See: https://github.com/tablecheck/mongoid-ultra/actions/runs/4664431260/jobs/8256670566?pr=15

     Failure/Error: expect(client.cluster).to receive(:disconnect!).and_call_original
     
       (#<Mongo::Cluster:0x954120 servers=[#<Mongo::Server:0x954220 address=localhost:27017 PRIMARY>, #<Mongo::Server:0x954240 address=localhost:27018 SECONDARY>] topology=ReplicaSetWithPrimary[localhost:27017,localhost:27018,localhost:27019,name=repl0,v=1,e=7fffffff0000000000000001]>).disconnect!(*(any args))
           expected: 1 time with any arguments
           received: 0 times with any arguments
     # ./spec/mongoid_spec.rb:79:in `block (4 levels) in <top (required)>'
     # ./spec/lite_spec_helper.rb:74:in `block (3 levels) in <top (required)>'
     # ./spec/lite_spec_helper.rb:73:in `block (2 levels) in <top (required)>'