vets-api fix bugs from the simple froms migration

Summary

This PR is to fix a bug that was created during the migration from simple_forms folder to the ivc_champva folder. Some variables were not changed.

Related to: https://github.com/department-of-veterans-affairs/vets-api/pull/16091/files

Testing done

[ ] New code is covered by unit tests
Describe what the old behavior was prior to the change
Describe the steps required to verify your changes are working as expected. Exclusively stating 'Specs run' is NOT acceptable as appropriate testing
If this work is behind a flipper:
- Tests need to be written for both the flipper on and flipper off scenarios. Docs.
- What is the testing plan for rolling out the feature?

What areas of the site does it impact?

This only impacts the ivc_champava forms

Acceptance criteria

[ ] I fixed|updated|added unit tests and integration tests for each feature (if applicable).
[ ] No error nor warning in the console.
[ ] Events are being sent to the appropriate logging solution
[ ] Documentation has been updated (link to documentation)
[ ] No sensitive information (i.e. PII/credentials/internal URLs/etc.) is captured in logging, hardcoded, or specs
[ ] Feature/bug has a monitor built into Datadog or Grafana (if applicable)
[ ] If app impacted requires authentication, did you login to a local build and verify all authenticated routes work as expected
[ ] I added a screenshot of the developed feature

Requested Feedback

(OPTIONAL)What should the reviewers know in addition to the above. Is there anything specific you wish the reviewer to assist with. Do you have any concerns with this PR, why?

Apr 19 '24 13:04 cloudmagic80

Error: A file (or its parent directories) does not have a CODEOWNERS entry. Please update the .github/CODEOWNERS file and add the entry for the Offending file: modules/ivc_champva/app/services/ivc_champva/pdf_filler.rb