YamlPlugin: Option without children

[simisimon]

The analysis of elasticsearch failed due to an IndexError in conflict_detector.py

2022-01-15 07:55:01,255 |     INFO |             launcher | Analyzing network for elasticsearch.
2022-01-16 11:38:36,053 |    ERROR |             analyzer | An exception occurred during analysis at commit 39ccc67a7bc19f7dbce2468bd3a0ad8ebd5bcaa0.
2022-01-16 11:38:36,054 |    ERROR |             analyzer | list index out of range

I tried to reproduce this error corresponding commits using some additional logging messages.
I got the the following:

2022-01-17 09:56:14,075 |     INFO |             launcher | Validate configuration network
2022-01-17 09:56:15,475 |    ERROR |    conflict_detector | Option a does not contain a child: elasticsearch::::post_data.yaml::::Test POST data with invalid parameters::::Test POST data with invalid parameters_1::::do::::xpack.ml.p

It seems that the last line in the example below caused the error.

"Test POST data with invalid parameters":
  - skip:
      features: ["headers"]

  - do:
      #set the header so we won't randomize it
      headers:
        Content-Type: application/json
      catch: missing
      xpack.ml.post_data:
        job_id: not_a_job
        body: {}