[No QA] Docs updates for E/A#94047 Hide Getting started when onboarding complete

[MelvinBot]

Why this change

E/A#94047 changed the behavior of the Getting started section on Home: it now disappears as soon as every onboarding to-do is complete, instead of lingering for the full 60-day onboarding window. The 60-day window now only acts as an upper bound for members who still have outstanding to-dos.

The Expensify Home Overview article documented only the appearance conditions and implied the section stays for the full window, so it no longer reflected current behavior.

What changed

docs/articles/new-expensify/getting-started/Expensify-Home-Overview.md:

• How the Getting started section works on Home — added a note that the section is hidden as soon as every checklist item is complete, and clarified the onboarding window is only an upper limit for members with remaining setup steps.
• FAQ — Why don't I see the Getting started section? — added that the section is also hidden once you've completed every checklist item, even within the 60-day window.

No new UI labels were introduced; the existing Getting started, manage my team, and track and budget my expenses terminology was preserved verbatim.

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@adamgrzybowski, please review the files changed and confirm they reflect the current behavior. Then mark this PR Ready for review.

[OSBotify]

A preview of your ExpensifyHelp changes have been deployed to https://4677293c.helpdot.pages.dev ⚡️

Updated articles:

• articles/new-expensify/getting-started/Expensify-Home-Overview