[client] Prevent IndexError when reading Case-Incident in OpenCTIConnectorHelper

[jmbodelon]

_data_handler in opencti_connector_helper.py raises error "IndexError: list index out of range" when reading a Case-Incident

[aHenryJard]

Can you update the PR description to an actual description please, it look like it's a part of a commit message. It will be more easy to understand the context for review.

[aHenryJard]

Closing as I there is no anwser and update, feel free to reopen if you still need it.