Root spans aren't being detected by the integration tests (new Spin release)

When I run the unit tests with Spin v3.6.0, the integration tests aren't receiving the host spans (e.g `execute_wasm_component rust-spin-basic`, `GET /...`); however, the spans are being exported when I test manually with the `spin otel` plugin. We encountered this before, and it disappeared after some unrelated changes to Spin, and the issue seems to have reappeared.