Treat all 2xx ingestion responses as successful

[marandaneto]

Summary

Treat all 2xx ingestion responses as successful in the Ruby SDK.

Spec

• sdk-specs/openspec/specs/http-client/spec.md

Current evidence

The SDK audit found send paths treating only status == 200 as success; the spec expects any 2xx response to be considered successful.

Expected behavior

• Classify HTTP 2xx responses as success for ingestion sends.
• Avoid invoking error handling for successful 2xx responses.
• Preserve existing handling for retryable/non-retryable failures.
• Add tests for non-200 2xx statuses, e.g. 201/202/204.