migrate Datadog Test Optimization setup to use the new datadog-ci gem

[anmarchenko]

What does this PR do?

Migrates Datadog Test Optimization product (aka tracing tests) from outdated ddtrace gem to new datadog-ci gem

Review checklist

Please check relevant items below:

• N/A - This PR includes all newly recorded cassettes for any modified tests.

• This PR does not rely on API client schema changes.

  • The CI should be fully passing.

[datadog-datadog-prod-us1]

Datadog Report

Branch report: anmarchenko/update_datadog_ci_setup
Commit report: 1e34e97
Test service: datadog-api-client-ruby

✅ 0 Failed, 2821 Passed, 59 Skipped, 2m 40.59s Total Time
❄️ 11 New Flaky

New Flaky Tests (11)

• Get all application keys returns "OK" response - Key Management at features/v2/key_management.feature

• Create a Basic HTTP custom destination returns "OK" response - Logs Custom Destinations at features/v2/logs_custom_destinations.feature

• Create a Custom Header HTTP custom destination returns "OK" response - Logs Custom Destinations at features/v2/logs_custom_destinations.feature

• Create an Elasticsearch custom destination returns "OK" response - Logs Custom Destinations at features/v2/logs_custom_destinations.feature - Last Failure

  Expand for error

   
   expected: 200
        got: 422
   
   (compared using ==)
   
  

• Create a Splunk custom destination returns "OK" response - Logs Custom Destinations at features/v2/logs_custom_destinations.feature