Enhance e2e test for HotROD

[yurishkuro]

The existing CI test for HotROD scripts/hotrod-integration-test.sh only checks that the HotROD web UI is being served after running docker compose. Since OTEL Collector release v0.105 there was a change where OTLP receivers started using localhost as the default host to listen to (see #5734). This breaks visibility of Jaeger endpoints from HotROD app, but our CI tests did not fail, because scripts/hotrod-integration-test.sh doesn't actually check if the trace is successfully submitted to Jaeger.

We can do better. While we cannot simulate a click on the UI button in the test (technically, we can with a headless browser), we can still execute a request against HotROD's frontend service endpoint, which will trigger a trace generation into Jaeger. The endpoint should also return the trace ID in the response headers. Using that trace ID the test can poll Jaeger query for that trace, checking that the expected number of spans is present (retry until that number is returned or until a global timeout is reached, e.g. 5min).

[hellspawn679]

when i run hotrod container it shows this
traces export: Post "http://localhost:4318/v1/traces": dial tcp 127.0.0.1:4318: connect: connection refused
and i ran jaeger container using this command

docker run -d --name jaeger \
  -p 16686:16686 \
  -p 4317:4317 \
  -p 4318:4318 \
  -e LOG_LEVEL=debug \
  -e COLLECTOR_OTLP_GRPC_HOST_PORT=0.0.0.0:4317 \
  -e COLLECTOR_OTLP_HTTP_HOST_PORT=0.0.0.0:4318 \
  jaegertracing/all-in-one:${JAEGER_VERSION:-latest}

[hellspawn679]

@yurishkuro I think it is trying to hit http://localhost:4318 inside the hotrod container

[yurishkuro]

probably same issue as here #5734