[v9] Remove non-normalized request handling in `requestDataIntegration`

[mydea]

Description

Today, we have two ways to add request data to events in requestDataIntegration:

1. Recently added via normalizedRequest on the SDK processing metadata, which is pre-processed
2. The "old" way of request on the SDK processing metadata which is processed in the integration

In v9, we want to remove the old request variant, and only rely on the normalizedRequest.

Related to this, we may also clean up the types & type names for this.

Follow up to #14298