fix(buildkite): improve error handling for HTTP requests and add fallback for 404 responses

[MattDevy]

Elasticsearch version 9.1.0-SNAPSHOT doesn't exist in https://artifacts-api.elastic.co/v1/versions/9.1.0-SNAPSHOT in these cases we should fallback to version without -SNAPSHOT

Fixes buildkite test issue on main (and 9.1 branch)

See error:

INFO: Retrieving Elasticsearch Version & Hash from container...
--
  | INFO: Download Elasticsearch specs...
  | 2025/11/09 00:04:22 0 builds found
  | 2025/11/09 00:04:22 Build found :
  | 2025/11/09 00:04:22 Zipfile url :
  | 2025/11/09 00:04:22 Cannot download zip from , reason : Get "": unsupported protocol scheme ""

[prodsecmachine]

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