Mobile: Update appointments to use VAOS for local time

[Tonksthebear]

Summary

VAOS now provides the converted local time, so this ticket migrates mobile to use this new field

Related issue(s)

• department-of-veterans-affairs/va.gov-team#5578

Testing done

Existing test coverage should handle the changes

What areas of the site does it impact?

Mobile appointments endpoint

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?

[ryan-mcneil]

👌

[kpethtel]

Looks good. Any tests for the new case?

[Tonksthebear]

Looks good. Any tests for the new case?

The existing tests should cover it I believe. The existing tests already hit cases where VAOS would return nil or the error message in start_local_time so they hit the fallback code as is