Add disable_keep_alives configuration option to Zipkin receiver

[ghost]

Description

This PR adds support for disabling HTTP keep-alive connections in the Zipkin receiver by introducing a new disable_keep_alives configuration option.

HTTP keep-alive connections can sometimes cause issues in high-load environments or when using certain load balancers. Users need the ability to disable keep-alive behavior to:

• Better control resource usage in containerized environments
• Ensure connections are properly closed after each request
• Work around proxy/load balancer limitations
• Match behavior expectations from other tracing systems

Usage Example

receivers:
  zipkin:
    disable_keep_alives: true
    endpoint: "localhost:9411"

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: Parship999 / name: Parship Chowdhury (4e79eb7, 59134e7)

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[ghost]

@evan-bradley Can you please review it?
And please help me to fix the failed checks

[atoulme]

Please take a look at the lint failures:

receiver/zipkinreceiver/trace_receiver_test.go:539:35: context.Background() could be replaced by t.Context() in TestKeepAliveConfig (usetesting)

Please add a changelog make chlog-new

[atoulme]

Once addressed, please mark ready for review again and we will kick off the CI.

[ghost]

Once addressed, please mark ready for review again and we will kick off the CI.

Done

[yurishkuro]

why does this need to be part of zipkin config and not confighttp.ServerConfig?

[ghost]

ok i now understood, after it will be added to confighttp.ServerConfig, this would make it available to all HTTP receivers not just Zipkin

[atoulme]

That's right, please open an issue in https://github.com/open-telemetry/opentelemetry-collector and link it here

[ghost]

I actually already opened a PR for this here: open-telemetry/opentelemetry-collector#13783