Rename argument in get_supplemental_claim_upload

[kayline]

Summary

• This work is behind a feature toggle (flipper): NO
• was :uuid, now :guid
• to match get_notice_of_disagreement_upload for easier code sharing and shared testing
• Decision Reviews, yes

Related issue(s)

department-of-veterans-affairs/va.gov-team#96645

Testing done

• New code is covered by unit tests
• Changed one named argument from :uuid to :guid

What areas of the site does it impact?

DecisionReviewV1::Appeals::SupplementalClaimServices

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 (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

[shaunburdick]

LGTM!