In the multi region and original Cluster action --> EditMachinePoolModal.tsx, the type of Cluster is being used for the cluster object, but we will need to refactor it to use ClusterFromSubscription similar to how many other of the ClusterDetails components use the type of ClusterFromSubscription, see discussion in merge request 6119

Items include:

• Refactor use of type Cluster to ClusterFromSubscription for multi region and original EditMachinePoolModal.tsx, child components and helper functions
• Remove display_name from type Subscription in src/types/clusters_mgmt.v1/models/Subscription.ts 
• After changing type of Cluster to ClusterFromSubscription use helper function getClusterName to display the display name for the EditMachinePoolModal.tsx component