Adding COMM Leadership QBR attendee list & CS leadership to QBR Handbook pg

Why is this change being made?

In addition to carrying over invite lists from one quarter to another for COMM Leadership QBRs, we also need to update the role-based invite list so that attendees are repeatable and scalable even with team changes. Updating that list to reflect @ronell's preferred role-based attendees here.

Author Checklist

• Provided a concise title for the MR
• Added a description to this MR explaining the reasons for the proposed change, per say-why-not-just-what
• Assign this change to the correct DRI
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