Update Zendesk app docs to reflect current state

Why is this change being made?

Support ops have updated the restrictions for some of Zendesk apps that support uses and switch them from being role-based to group-based. This changed is to update the documentation to reflect the current state of our Zendesk instance.

Author Checklist

• Provided a concise title for this Merge Request (MR)
• Added a description to this MR explaining the reasons for the proposed change, per say why, not just what
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  • If this is a change that directly impacts the majority of global team members, it should be a candidate for #company-fyi. Please work with internal communications and check the handbook for examples.

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