Fix message detection to match actual OpenHands messages

[neubig]

This PR fixes the message detection logic to match the actual messages sent by OpenHands:

• Issue success: When a draft PR is created
• Issue failure: When the workflow fails or no changes are made
• PR success: When changes are pushed to the PR
• PR failure: When the workflow fails or no changes are made

The messages are taken from:

• openhands/resolver/send_pull_request.py
• .github/workflows/openhands-resolver.yml

I have also updated the tests to use these exact messages in their mock data and verified that the integration tests pass with real data from the OpenHands repository.

[vercel]

@openhands-agent is attempting to deploy a commit to the all-hands-ai team on Vercel, but is not a member of this team. To resolve this issue, you can:

• Make your repository public. Collaboration is free for open source and public repositories.
• Add @openhands-agent as a member. A Pro subscription is required to access Vercel's collaborative features.
  • If you're the owner of the team, click here and add @openhands-agent as a member.
  • If you're the user who initiated this build request, click here to request access.
  • If you're already a member of the all-hands-ai team, make sure that your Vercel account is connected to your GitHub account.

To read more about collaboration on Vercel, click here.