ref(core): Drop provider specific attributes not part of sentry conventions #20015

In the openai and anthropic integrations we send multiple provider specific attributes. None of these are part of our sentry conventions and should therefore be emitted. These fall into two categories:

• Exact duplicates of attributes in our gen_ai namespace:
  • openai.response.id, openai.response.model, openai.usage.prompt_tokens, openai.usage.completion_tokens
  • These are strictly redundant and therefore provide no value.
• No gen_ai equivalent:
  • openai.response.timestamp, anthropic.response.timestamp
  • These have no gen_ai equivalent so we would no longer send this data at all, but since they are not in the semantic conventions we probably shouldn't send them either.

According to Hex, none of these attributes are used in any stored queries, dashboards or alerts. I am aware that users could still use these attributes in hooks so it could technically be interpreted as a breaking change. Let me know if you think this is fine to remove as is or if we should handle this a bit more graciously (e.g. mention in the changelog, or wait for the next major).