[No QA] Docs updates for E/A#88363 Add billing restriction note to duplicate docs

[MelvinBot]

Summary

• Updates the How to Duplicate an Expense help article to note that users with an expired billing subscription on their primary workspace will be prompted to add a payment card before duplicating
• Updates the Duplicate a Report help article with the same billing restriction note
• Adds a new FAQ entry to both articles explaining the payment card prompt

These changes document the new billing restriction guard added to duplicate expense/report handlers in #88363.

Test plan

• Verify the updated articles render correctly on the help site
• Confirm the new FAQ entries are clear and match the actual UI behavior

[OSBotify]

A preview of your ExpensifyHelp changes have been deployed to https://30384835.helpdot.pages.dev ⚡️

Updated articles:

• articles/new-expensify/reports-and-expenses/Duplicate-a-Report
• articles/new-expensify/reports-and-expenses/How-to-Duplicate-an-Expense