Use YAML.load to load classes beyond the basic types

https://bugzilla.redhat.com/show_bug.cgi?id=1789153

Followup to ManageIQ/manageiq#19701

We're trying to load MiqAeMethodService::MiqAeServiceService and
ActiveSupport::HashWithIndifferentAccess in these places.  The prior behavior in
core was to treat YAML.safe_load like YAML.load so let's change these to .load
for now.  If we want to use safe_load, we'll need to enumerate all of the
additional classes we want to allow to be loaded beyond the ruby basic types.

spec/engine/miq_ae_method_service/miq_ae_service_model_base_spec.rb

@@ -104,13 +104,13 @@
     end
 
     it 'loads object from yaml' do
-      expect(YAML.safe_load(svc_service.to_yaml)).to eq(svc_service)
+      expect(YAML.load(svc_service.to_yaml)).to eq(svc_service)
     end
 
     it 'loads invalid svc_model for objects without related ar_model' do
       yaml = svc_service.to_yaml
       service.delete
-      model_from_yaml = YAML.safe_load(yaml)
+      model_from_yaml = YAML.load(yaml)
       expect { model_from_yaml.reload }.to raise_error(
         NoMethodError,
         "undefined method `reload' for nil:NilClass"

spec/engine/miq_ae_state_machine_retry_spec.rb

@@ -280,6 +280,6 @@ def create_restart_model(script1, script2, script3)
     expect(MiqQueue.count).to eq(2)
     q = MiqQueue.where(:state => 'ready').first
     expect(q[:server_guid]).to be_nil
-    expect(YAML.safe_load(q.args.first[:ae_state_data])).to eq(ae_state_data)
+    expect(YAML.load(q.args.first[:ae_state_data])).to eq(ae_state_data)
   end
 end