DEVDOCS-6211 - update concurrent call limit (category trees)

[bc-terra]

Added messaging about concurrent call rate limit to Get a Category Tree endpoint. This will be affected by an experiment in the next 90 days.

DEVDOCS-6211

What changed?

• The Get a Category Tree endpoint is getting a concurrent call limit to prevent overloading on the back-end.
• This endpoint is now documented.

Release notes draft

• Updated Get a Category Tree endpoint to include mention of the default concurrent call limit.

Anything else?

ping {names}

[jyuricle]

We should put in on hold until all the blockers are addressed