[DO NOT MERGE] Add Watch Data endpoints to OpenAPI spec

[bot-api-video]

Changes are for this Asana task.

I am creating this PR in order to trigger the action that moves the changes to the api.video-documentation repo's staging.

⚠️ DO NOT MERGE ⚠️

Summary

• Added 3 new endpoints based on the Watch Data API specification, with all required schema components and examples.
  • /data/buckets/{metric}/{breakdown}
  • /data/metrics/{metric}/{aggregation}
  • /data/timeseries/{metric}
• Updated the 429 - Too many requests response title

Created by @olivierapivideo via https://github.com/apivideo/api.video-api-client-generator/pull/379