Set ref mns_environment to int

Author: amarauzoma

infrastructure/instance/environments/dev/ref/variables.tfvars

@@ -2,7 +2,7 @@ environment                       = "dev"
 immunisation_account_id           = "345594581768"
 dspp_core_account_id              = "603871901111"
 pds_environment                   = "ref"
-mns_environment                   = "dev"
+mns_environment                   = "int"
 mock_pds_enabled                  = true
 mock_pds_average_rate_limit       = 125
 mock_pds_spike_rate_limit         = 450