Fix endpoint telemetry request body

What Does This Do
Change request-body-type to request_body_type to mach the defined schema

Add optional fields to endpoint unit tests

Motivation
The current implementation of endpoint discovery for API Security does not match the latest version of the RFC.

Additional Notes
https://docs.google.com/document/d/1txwuurIiSUWjYX7Xa0let7e49XKW2uhm1djgqjl_gL0/edit?tab=t.0

Author: jandro996

telemetry/src/main/java/datadog/telemetry/TelemetryRequestBody.java

@@ -329,7 +329,7 @@ public void writeEndpoint(final Endpoint endpoint) throws IOException {
     bodyWriter.name("operation_name").value(endpoint.getOperation());
     bodyWriter.name("resource_name").value(endpoint.getResource());
     if (endpoint.getRequestBodyType() != null) {
-      bodyWriter.name("request-body-type").jsonValue(endpoint.getRequestBodyType());
+      bodyWriter.name("request_body_type").jsonValue(endpoint.getRequestBodyType());
     }
     if (endpoint.getResponseBodyType() != null) {
       bodyWriter.name("response_body_type").jsonValue(endpoint.getResponseBodyType());

telemetry/src/test/groovy/datadog/telemetry/TelemetryServiceSpecification.groovy

@@ -26,7 +26,7 @@ class TelemetryServiceSpecification extends DDSpecification {
   def distribution = new DistributionSeries().namespace("tracers").metric("distro").points([1, 2, 3]).tags(["tag1", "tag2"]).common(false)
   def logMessage = new LogMessage().message("log-message").tags("tag1:tag2").level(LogMessageLevel.DEBUG).stackTrace("stack-trace").tracerTime(32423).count(1)
   def productChange = new ProductChange().productType(ProductChange.ProductType.APPSEC).enabled(true)
-  def endpoint = new Endpoint().first(true).type('REST').method("GET").operation('http.request').resource("GET /test").path("/test")
+  def endpoint = new Endpoint().first(true).type('REST').method("GET").operation('http.request').resource("GET /test").path("/test").requestBodyType(['application/json']).responseBodyType(['application/json']).responseCode([200]).authentication(['JWT'])
 
   def 'happy path without data'() {
     setup: