Automate Fleet-27

[sbulage]

In this test achieve below things:

• [x] Create ClusterGroup with 2 clusters by using label on clusters.
• [x] Create GitRepo by targeting ClusterGroup to deploy application on both clusters
• [x] Check application status on each clusters(2 clusters)
• [x] Add third cluster to existing clusterGroup by adding label to it.
• [x] Check Cluster Group that newly labeled cluster is part of that or not.
• [x] Check application is deployed on (newly added cluster in clustergroup) third cluster