Typo in parameter name for services API endpoint

What does this MR do?

Found a typo in a parameter name for the hipchat service create/edit endpoint here. I git grep'd the source and it looks like the parameter name is just wrong in the API and that the underlying code is fine (not an actual functional bug). Typo is confidental_note_events which should be confidential_note_events

Screenshots

N/A

Does this MR meet the acceptance criteria?

This should just be a documentation change (@gl-docsteam per here)

Conformity

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Security

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