(PE-39352,PE-39351) Gather PE version in get_peadm_config task

Adds a lookup of the pe_build file to provide the PE version in the hash
returned by the get_peadm_config task.

We will use this in add_database and backup/restore plans as a version
gate for handling the newer host_action_collector database that is only
present in PE 2023.7+, for example.

tasks/get_peadm_config.rb

@@ -41,6 +41,7 @@ def config
 
     # Build and return the task output
     {
+      'pe_version' => pe_version,
       'params' => {
         'primary_host' => primary,
         'replica_host' => replica,
@@ -73,6 +74,12 @@ def config
     }
   end
 
+  # @return [String] Local PE version string.
+  def pe_version
+    pe_build_file = '/opt/puppetlabs/server/pe_build'
+    File.read(pe_build_file).strip if File.exist?(pe_build_file)
+  end
+
   # Returns a GetPEAdmConfig::NodeGroups object created from the /groups object
   # returned by the classifier
   def groups