Move the CE/CC instructions to a state in the past

Why is this change being made?

This is part of the onboarding checklist https://gitlab.com/gitlab-com/team-member-epics/employment/-/issues/3893 where I was asked to make a change in the handbook. That said, the information in the handbook is not quite accurate and can become confusing when reading the information about CE/CC distributions. It is a state of the past and should be reflected as such. Removing the information is not recommended as it is possible companies of people are still using these terms.

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
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  • 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 in on the page being edited.
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• 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.

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