Revert changes

.circleci/config.yml

@@ -2,7 +2,6 @@ version: 2.1
 
 orbs:
   slack: circleci/slack@4.2.0
-  grafana: grafana/k6@1.1.3
 
 slack-fail-post-step: &slack-fail-post-step
   post-steps:
@@ -464,8 +463,6 @@ jobs:
           path: tests/_output
   performance_tests:
     working_directory: /home/circleci/mailpoet/mailpoet
-    executor: grafana/k6
-    cloud: true
     machine:
       image: ubuntu-2204:2022.10.2
       docker_layer_caching: false