Clean-up old office hours refs

[janan07]

Describe your pull request here: The ZoweDocs Office Hours reference page: https://docs.zowe.org/stable/whats-new/zowe-v3-office-hours/

Should only contain the most current v3 office hours series (beginning 9/6/2024)

List the file(s) included in this PR: zowe-v3-office-hours.md and same file in v2.18

After creating the PR, follow the instructions in the comments.

See zowe/community#2322

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[github-actions]

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