dog event post does not type --related_event_id properly

[gchpaco]

Describe the bug
I expect dog event post to work when given a related event ID; for example

dog event post --related_event_id 4 foo bar

should work. What it actually does is return

ERROR: Invalid JSON structure

To Reproduce
Steps to reproduce the behavior:

1. Post an event, and extract the event ID.
2. Post a second event and pass the first event ID as a related event
3. See error

Expected behavior
I would expect it to work and for the backend API to tie the two together.

Environment and Versions (please complete the following information):

• dog 0.46.0
• Python 3.11.2

[github-actions]

Thanks for your contribution!

This issue has been automatically marked as stale because it has not had activity in the last 30 days. Note that the issue will not be automatically closed, but this notification will remind us to investigate why there's been inactivity. Thank you for participating in the Datadog open source community.

If you would like this issue to remain open:

1. Verify that you can still reproduce the issue in the latest version of this project.

2. Comment that the issue is still reproducible and include updated details requested in the issue template.