Skip deprecation warnings bad request for Serverless or Environment providers

[mrodm]

This PR ignores or skip the deprecation warnings validation for Serverless and Environment providers.

In case of Serverless, it is skipped directly.
In case of the Environment provider, it is tried to validate the warnings. However, if the query returns status code 400 (Bad Request), the error is ignored.

Example of the error found in a Serverless project trying to run some system tests:

--- Test results for package: elastic_package_registry - START ---
╭──────────────────────────┬─────────────┬───────────┬───────────┬─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┬───────────────╮
│ PACKAGE                  │ DATA STREAM │ TEST TYPE │ TEST NAME │ RESULT                                                                                                                                                                                                                                                                                          │  TIME ELAPSED │
├──────────────────────────┼─────────────┼───────────┼───────────┼─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┼───────────────┤
│ elastic_package_registry │ metrics     │ system    │ default   │ ERROR: failed to get deprecation warnings for data stream metrics-elastic_package_registry.metrics-62481: unexpected status code in response: [400 Bad Request] {"error":"no handler found for uri [/metrics-elastic_package_registry.metrics-62481/_migration/deprecations] and method [GET]"} │ 49.985708659s │
╰──────────────────────────┴─────────────┴───────────┴───────────┴─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┴───────────────╯

Author's checklist

• Tested the changes running system tests with a Serverless project.

2025/04/03 18:16:47 TRACE Skip deprecation warnings in Serverless projects
2025/04/03 18:16:47 DEBUG Found 0 deprecation warnings for data stream metrics-elastic_package_registry.metrics-33382

[jsoriano]

👍