[RelayMiner] Improve non-2xx errors visibility, do not mine 5xx

[red-0ne]

Summary

Enhance error logging for non-2xx HTTP responses and prevent 5xx server errors from entering the reward pipeline

Primary Changes:

• Add detailed logging for non-2xx responses including request_url, request payload snippets, and response payload snippets for better debugging
• Prevent 5xx server errors from entering the reward pipeline to avoid rewarding failed backend services
• Refactor response serialization to occur before error logging for consistent payload access

Secondary changes:

• Improve code comments for clarity on reward eligibility conditions
• Reorganize response handling flow for better error visibility

Issue:

Problem: Non-2xx HTTP responses lacked sufficient debugging information and 5xx server errors were incorrectly entering the reward pipeline, potentially rewarding failed backend services.

Type of change

Select one or more from the following:

• New feature, functionality or library
• Bug fix
• Code health or cleanup
• Documentation
• Other (specify)

Sanity Checklist

• I have updated the GitHub Issue Metadata: assignees, reviewers, labels, project, iteration and milestone
• For docs: make docusaurus_start
• For small changes: make go_develop_and_test and make test_e2e
• For major changes: devnet-test-e2e label to run E2E tests in CI
• For migration changes: make test_e2e_oneshot
• 'TODO's, configurations and other docs

[github-actions]

The CI will now also run the e2e tests on devnet, which increases the time it takes to complete all CI checks.

You may need to run make trigger_ci to submit an empty commit that'll trigger the tests.

GCP workloads (requires changing the namespace to 1695)
Grafana network dashboard for devnet-issue-1695