fix: bug in service dependsOn where services become !Deployed

[wahabmk]

Description

Kindly see the description of the bug in the linked issue. The fix that this PR proposes is explained by the following scenario:

• Let's say a CD or MCS with services A<-(B,C) has been created, i.e: B and C depend on A.
• The controller will first add A to the ServiceSet.
• Then B & C are added to ServiceSet once A is successfully deployed.
• So all 3 services eventually become successfully deployed.
• Now let's say for some reason the state of A changes to !Deployed (maybe Failed or Provisioning) in the ClusterSummary.
• Now the poller is triggered again to reconcile the ServiceSet.
• The ServiceSet is updated with the latest state of services from ClusterSummary, this in-turn triggers the CD or MCS controller.
• Originally the controller would only include A in the ServiceSet because A's current state doesn't show Deployed and B & C depend on A so they shouldn't be added to the ServiceSet until A has been deployed (the bug)
• Now with this change, once the controller observes that A's state is !Deployed, it will check if any of A's dependents already exist in the current ServiceSet's spec. If yes, then that means A was successfully deployed in the past, therefore, it will add all of A's dependents to the ServiceSet even if currently A's state shows !Deployed.

Fixes: #2377.