docs: add hook import information to Pay with Exchange documentation

[devin-ai-integration]

Description

Added a Note block to the Pay with Exchange documentation clarifying that all hooks must be imported from @reown/appkit-pay/react. This addresses user confusion about where to import hooks like useAvailableExchanges, usePayUrlActions, and useExchangeBuyStatus.

The change was made to the shared snippet file (snippets/appkit/shared/appkit-pay-react.mdx) which is used across React-based framework documentation pages (React, Next.js, etc.).

Link to Devin run: https://app.devin.ai/sessions/22e5974aca4e4d8e80b1dabb9a255919
Requested by: TomTom (tomas.rawski@reown.com)

Tests

• - Ran the changes locally with Mintlify and confirmed that the changes appear as expected.
• - Ran a grammar check on the updated/created content using ChatGPT.

Direct link to the deployed preview files

• Pay with Exchange - React
• Pay with Exchange - Next.js

Review Checklist

• Verify the Note component renders correctly in the Mintlify preview deployment
• Confirm the import path @reown/appkit-pay/react is accurate for all three hooks
• Consider if similar clarification is needed for JavaScript/Vue framework pages

[devin-ai-integration]

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