Fix Exporter Joint Saving [AARD-2063]

[rutmanz]

Task

AARD-2063

Symptom

Passing joints between the exporter web ui and exporter was failing due to a mismatched key name

Solution

I fixed the build command to run type checking (so this doesn't happen again) and fixed the property key

Verification

You can open the exporter ui, add joints, save, reload, and still see your joints

Before merging, ensure the following criteria are met:

• All acceptance criteria outlined in the ticket are met.
• Necessary test cases have been added and updated.
• A feature toggle or safe disable path has been added (if applicable).
• User-facing polish:
  • Ask: "Is this ready-looking?"
• Cross-linking between Jira and GitHub:
  • PR links to the relevant Jira issue.
  • Jira ticket has a comment referencing this PR.