Bug: PATCH cancellations sent to VPG have no request body

Summary

While attempting to cancel an OH appointment an error was received back from VPG. Describe what went wrong

Specs

Browser: Chrome

Steps to Reproduce

Enable the

In Flipper, enable the va_online_scheduling_use_vpg and va_online_scheduling_enable_OH_cancellations feature flags for Judy Morrison
Go to VAOS, open an upcoming OH appointment
Click the cancellation button

Actual Result

VETSAPI sends a PATCH cancellation request to VPG with no request body, resulting in an error:

{
  "errors": [
    {
      "title": "Bad Request",
      "detail": "Required request body is missing: public org.springframework.http.ResponseEntity<?> gov.va.mobile.vpg.v1.resource.AppointmentResource.patchAppointment(org.springframework.cloud.gateway.mvc.ProxyExchange<byte[]>,java.lang.String,java.lang.String,java.lang.String,java.lang.String)",
      "code": "VAOS_400",
      "source": {
        "vamfUrl": "https://internal-dsva-vagov-staging-fwdproxy-1821450725.us-gov-west-1.elb.amazonaws.com:4463/vpg/v1/patients/434fce82be04d498f7e7e54f30c0d4c35f61bc4e53610137bcb446723597732a/appointments/38eb82d7451c9036df43fa75318a5453d1a66e3055ce09ebcec16821949e44cf",
        "vamfBody": "{\"code\":400,\"status\":400,\"message\":\"Required request body is missing: public org.springframework.http.ResponseEntity<?> gov.va.mobile.vpg.v1.resource.AppointmentResource.patchAppointment(org.springframework.cloud.gateway.mvc.ProxyExchange<byte[]>,java.lang.String,java.lang.String,java.lang.String,java.lang.String)\",\"id\":\"e16a2ff4-197c-4895-908f-96d1fcf13f3e\",\"traceId\":\"55fa6be23b2197b9f9c4d1a7975d21a6\"}",
        "vamfStatus": 400
      },
      "status": "400"
    }
  ]
}

Desired Result

VETSAPI sends the PATCH request to VPG with the patch operations in the request body.

Definition of Done

[X] Desired result is achieved and/or document decisions made
[ ] Relevant documentation is updated

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