Fix crash on save

[king-alexander]

🗣 Description

This is a simple change to extract the log_id from the cert_by_issuance task. The line of code broke when we switched APIs.

💭 Motivation and context

• Resolves #45

🧪 Testing

I didn't catch this bug earlier because I tested without saving certificates to the database. This time I did. I ran the load_certs script on the opensource.gov domain and successfully saved 100 certificates to the development database.

✅ Pre-approval checklist

• [x] This PR has an informative and human-readable title.
• [x] Changes are limited to a single goal - eschew scope creep!
• [x] All relevant type-of-change labels have been added.
• [x] I have read the CONTRIBUTING document.
• [x] These code changes follow cisagov code standards.
• [x] All new and existing tests pass.

✅ Pre-merge checklist

• [x] Finalize version.

✅ Post-merge checklist

• [x] Create a release.