Requirement

When we test storage implementations in e2e tests we should be using v2 Storage API

Problem

The existing e2e tests work off the v1 model which does not adequately represent some edge cases possible in OTLP data model, such as scope attributes.

Proposal

• Upgrade this write path to use v2 Storage API (TraceWriter)
• Remove unnecessary downgrades done in the tests themselves, leave the downgrades to the storage implementations (when they don't yet support v2 API)
• Incrementally swap test fixtures to be stored as OTLP JSON instead of v1 model JSON

Open questions

No response