[JENKINS-75187] Unable to Connect to Agents

[jmdesprez]

Fix for https://issues.jenkins.io/browse/JENKINS-75187

Two fixes:

• misplaced }
• in the ServerKeyVerifier, convert the key to openSSH format

Testing done

Tested locally with:

• an empty init script
• all possible "Host Key Verification Strategy"

Submitter checklist

• Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
• Ensure that the pull request title represents the desired changelog entry
• Please describe what you did
• Link to relevant issues in GitHub or Jira
• Link to relevant pull requests, esp. upstream and downstream changes
• Ensure you have provided tests - that demonstrates feature works or fixes the issue

[PereBueno]

LGTM

[PereBueno]

@res0nance as per @jmdesprez comment, this fixes the bug introduced in https://github.com/jenkinsci/ec2-plugin/releases/tag/1822.v87175d209b_b_5
Could you review it?

[pankajy-dev]

LGTM