Use correct service connection for cosmos sub (#37458)

Author: weshaggard

sdk/cosmos/tests.yml

@@ -9,7 +9,7 @@ extends:
           SubscriptionConfigurations:
             - $(sub-config-azure-cloud-test-resources)
             - $(sub-config-cosmos-azure-cloud-test-resources)
-          ServiceConnection: azure-sdk-tests    
+          ServiceConnection: azure-sdk-tests-cosmos
       MaxParallel: 6
       BuildTargetingString: azure-cosmos
       ServiceDirectory: cosmos