Remove Needs Collaboration view and workflow from Support handbook

What?

Removes all mention of Needs Collaboration workflows and ZD view from Support handbook.

Closes gitlab-com/support/support-team-meta#4209 (closed)

Why is this change being made?

1. Hardly anybody uses it
2. There has been no feedback shared in favor of keeping Needs Collaboration view in gitlab-com/support/support-team-meta#4209 (closed)
3. Minimizing unused/unhelpful shared views leaves room to add new/helpful shared views in the future
4. Needs collaboration workflow conflicts with SGG workflows. The primary responsibility of Support engineers has changed from ensuring success of customers and our global team to ensuring the success of our specific Support Global group. Helping others with tickets Needs Collaboration view does not contribute to the success of our specific SGG.

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
  • Copy/paste the Slack conversation to document it for later, or upload screenshots. Verify that no confidential data is added.
• Assign reviewers for this MR to the correct Directly Responsible Individual/s (DRI)
  • If the DRI for the page/s being updated isn’t immediately clear, then assign it to one of the people listed in the Maintained by section on the page being edited
  • If your manager does not have merge rights, please ask someone to merge it AFTER it has been approved by your manager in #mr-buddies
• If the changes affect team members, or warrant an announcement in another way, please consider posting an update in #whats-happening-at-gitlab linking to this MR
  • 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.

---