ucs_server_maintenance doesn't properly handle empty trigger_config attribute

[gve-vse-tim]

When trigger_config is not specified in the task, Ansible 2.10 complains about a value not matching the valid choices of "on-next-boot":

failed: [ci-ucs] (item={'name': 'CI-Immediate', 'uptime_disr': 'immediate', 'state': 'present'}) => {"ansible_loop_var": "item", "changed": false, "item": {"name": "CI-Immediate", "state": "present", "uptime_disr": "immediate"}, "msg": "value of trigger_config must be one of: on-next-boot, got: "}

When I do specify the trigger_config for uptime_disr with value 'immediate', I get the proper error from UCS that the combination is not possible:

failed: [ci-ucs] (item={'name': 'CI-Immediate', 'uptime_disr': 'immediate', 'trigger_config': 'on-next-boot', 'state': 'present'}) => {"ansible_loop_var": "item", "changed": false, "item": {"name": "CI-Immediate", "state": "present", "trigger_config": "on-next-boot", "uptime_disr": "immediate"}, "msg": "setup error: [ErrorCode]: 1[ErrorDescription]: On next boot can only be set along with User Ack/Timer Automatic "}

So, in the current state, you can't create any Server Maintenance policies of type "immediate". And, for all other types, you are forced to accept "on-next-boot" because otherwise you get an error when Ansible sees the missing attribute as an empty value, which is not in the permitted range of valid choices.

I'm using Python 3.7.9 for this particular example, Ansible 2.10, and UCSM SDK 0.9.10.