Covers the router span name fallback end to end, not just at the unit
level. Both apps get a `sentryTest.variants` entry, which the e2e matrix
expands into a second matrix row that rebuilds the app with
`traceLifecycle: 'stream'` and runs the suite again.

Ember is built by Vite, so the lifecycle is a plain env var
(`VITE_TRACE_LIFECYCLE`). Angular can't read `process.env` in the browser
bundle, so it uses the builder's `fileReplacements` to swap
`trace-lifecycle.ts` for `trace-lifecycle.streamed.ts` under a new
`streamed` build configuration.

The assert command sets `E2E_TEST_TRACE_LIFECYCLE`, which the specs read:
the streamed specs skip unless it is set, and the transaction-based specs
skip when it is, since span streaming emits spans rather than
transactions.