survey mini dapp guide added

[ayo-klaytn]

✨ Proposed Changes

Added survey mini dapp guide to mini dapps section

🗂️ Types of changes

• Minor Issues and Typos
• Major Content Contribution
• Others (e.g. platform-specific changes)

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✅ Checklist

• I have read the CONTRIBUTING GUIDELINES.
• I have added necessary documentation (if appropriate).
• Any dependent changes have been merged and published in downstream modules.

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