[crossdock] Replace sampling calls to agent with calls to collector

[yurishkuro]

Part of #4739 and #6081

In the crossdock integration tests the test driver tries to connect to the "agent" and test its sampling endpoint response. We need to

• redirect it to query the sampling endpoint in the collector instead
• remove "agent" related code

cc @mahadzaryab1

[sriganeshres]

@yurishkuro i want to work on this issue as it is my first contribution to this repository can you guide me.

[yurishkuro]

@mahadzaryab1 volunteered to guide

[Garvit-77]

Hey @yurishkuro
I was looking into this issue but faced some hurdles majorly :
what are Endpoints for OTEL Collector for sampling?

in the ports.go i was able to find that the exposed port == 5778(CollectorV2 sampling http port)

[yurishkuro]

https://www.jaegertracing.io/docs/1.62/apis/#remote-sampling-configuration-stable

[inosmeet]

Do we only need to change the sampling URL endpoint, or should we also refactor the naming? Or am I thinking about this the wrong way?
@yurishkuro @mahadzaryab1

[yurishkuro]

@inosmeet I updated description. Not sure what you mean by "refactor the naming"