Api 42872 coutry to coutrycode poa v2

[rockwellwindsor-va]

Summary

• Updates country => countryCode in 2122 and 2122a schemas
  • Updates REGEX in schema pattern to only allow 2 characters, matches the current stateCode REGEX
• Adjusts related tests
• Updates swagger documentation to reflect change

Related issue(s)

API-42872

Testing done

• [x] Updates made to existing tests for change

Screenshots

What areas of the site does it impact?

modified:   modules/claims_api/app/swagger/claims_api/v2/dev/swagger.json
modified:   modules/claims_api/app/swagger/claims_api/v2/production/swagger.json
modified:   modules/claims_api/spec/requests/v2/veterans/rswag_power_of_attorney_spec.rb

Acceptance criteria

• [x] I fixed|updated|added unit tests and integration tests for each feature (if applicable).
• [x] No error nor warning in the console.
• [ ] Events are being sent to the appropriate logging solution
• [x] Documentation has been updated (link to documentation)
• [x] 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

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?