Bug 1753338

Description of problem:
The details of this BZ are confusing but I will do my best to explain all the reproduction steps here. Essentially, if you create a custom button under a generic object class of the "Ansible Playbook" type, and point it at a playbook catalog item, create and add a generic object instance to a service under my service, then click the button to execute the playbook, it doesn't do anything. If the button is not associated with the generic object class, then it will execute.  

Version-Release number of selected component (if applicable):
5.11.0.25

How reproducible:
100%

Steps to Reproduce:
1. Enable embedded ansible role
2. Add a repo with some playbooks (e.g. https://github.com/ManageIQ/integration_tests_playbooks.git)
3. Add some Ansible credentials for a VMware provider
4. Create a catalog named "Catalog VMware"
5. Create a catalog item "VMware Catalog Item" under this catalog that executes a playbook, if you're using the above repo you can use e.g. "gather_all_vms_from_vmware.yml"
6. Order the service catalog and ensure that the playbook runs successfully
7. Now create a separate catalog "Test Custom Button"
8. Create a "generic" catalog item under this catalog "test custom button"
9. Order this service and ensure that the service appears under My Services
10. Create a generic object class "Test class"
11. Create a custom button of type "Ansible Playbook" that uses the catalog item "VMware Catalog Item", with "Request" -> "Order_Ansible_Playbook"
12. Create a generic object instance under "Test class"
13. Associate the generic object instance with the service "Test Custom Button"
    This can be done by REST action "add_resource" or by the rails console
14. Navigate to Services > My services > Services > Active Services > Test Custom Button
15. In the generic objects summary table, there should be one instance associated with the service, click this instance
16. Click the generic object quadicon
17. The custom button you created in step 11 should be displayed, click that button. 
18. Hit submit

Actual results:
The playbook is not executed, no trace of the playbook being triggered in the logs at all

Expected results:
The playbook should be executed

Additional info:
If you create a button in "Automation > Automate > Customization > Buttons > Generic Objects" (i.e. not associated with a generic object class, but does the same thing as the button in step 11) then this button also appears on the page in step 17, and clicking this button DOES result in the playbook being executed. 

I am not sure if this is a valid use case, but I would still expect it to work given that it works for the scenario in the sentence above. 

Note: there are several BZs associated with custom buttons that are associated with the generic object classes
bug 1753237, 1753281

It is not clear whether this is an embedded ansible issue or a generic object custom button issue.