[Nuxt 5] Fix SWR tracing

Currently, the SWR tests are skipped.

The Nitro 3 runtime shows that route rules are now represented as middleware descriptors.
`event.context.routeRules.cache.options.swr === true` rather than `event.context.routeRules.swr === true`

Debugging ideas: Logging the `event.context.routeRules` value in the test assertions. A better long-term solution may be using Nitro's public route-rules lookup API rather than reading internal context shapes.