(maint) Fix GetPEAdmConfig node group test for peadm cluster

The 'PE HA Replica' node group is present in all PE installations,
installed with or without PEADM. Switched this to check for the 'PE
Primary A' node group that a PEADM installation specifically creates.

Author: jpartlow

tasks/get_peadm_config.rb

@@ -11,9 +11,9 @@ class GetPEAdmConfig
   def initialize(params); end
 
   def execute!
-    # if there is no 'PE HA Replica' node group, it's not a peadm-configured cluster.
-    replica_group = groups.data.find { |obj| obj['name'] == 'PE HA Replica' }
-    if replica_group
+    # if there is no 'PE Primary A' node group, it's not a peadm-configured cluster.
+    peadm_primary_a_group = groups.data.find { |obj| obj['name'] == 'PE Primary A' }
+    if peadm_primary_a_group
       puts config.to_json
     else
       puts({ 'error' => 'This is not a peadm-compatible cluster. Use peadm::convert first.' }).to_json