fix: first pr comment logic (2nd attempt)

[MantisClone]

1. Replaced the previous REST API endpoint with the GitHub Search API, which provides more accurate results for finding PRs by a specific author in a specific repository
2. Used repo:${{ github.repository }} is:pr author:$PR_AUTHOR as the search query to find all PRs by this author to this specific repository
3. Added proper URL encoding for the search query
4. Extracted the total_count field from the search results to determine how many PRs this user has created
5. Added more detailed logging to help with troubleshooting

The GitHub Search API provides a more reliable way to check if a user has submitted PRs to a repository before. It's less likely to be affected by any backend connections between different GitHub accounts.

If for some reason this still doesn't work properly, then yes, using a completely different email address for testing would be a good approach to ensure the accounts are completely separate in GitHub's system.