Add Swagger Documentation for RepresentationManagement::V0::PdfGenerator2122Controller

[opticbob]

Background

The RepresentationManagement::V0::PdfGenerator2122Controller currently lacks Swagger documentation. This documentation is essential for API consumers to understand the available endpoints, request/response formats, and overall API structure. Adding Swagger documentation will improve the visibility, usability, and maintainability of this controller's API.

Tasks

• [x] Add Swagger documentation for the endpoint in RepresentationManagement::V0::PdfGenerator2122Controller.
• [x] Ensure that request parameters, response formats, and possible error codes are accurately documented.
• [x] Review and verify that the Swagger documentation renders correctly in the Swagger UI.

Acceptance Criteria

• [x] Swagger documentation is available for the endpoint in the RepresentationManagement::V0::PdfGenerator2122Controller.
• [x] Documentation is complete and accurately reflects the API's request/response structure.
• [x] The Swagger UI displays the documentation correctly without errors.

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How to configure this issue

1. Label with practice area (backend, frontend,ux, design, research)
2. Label for MVP work? (mvp)
3. Add an estimate
4. Attach an Epic (what body of work is this a part of?)

[opticbob]

Finished with the 2122 class, converting the existing power of attorney docs to Swagger::Blocks format for this PR.

[opticbob]

After discussions with @jvcAdHoc and @holdenhinkle we're going to move away from the Swagger::Blocks format for this work and use rswag instead. It it already in use within vets-api and supports the latest openapi/swagger specification. It is also frequently updated while Swagger::Blocks was last updated 5 years ago.