This commit doesn't change the behavior wrt caching, but it makes it
more explicit that only non-timed-out responses are cached. In case of a
timeout, `res` would be set to a programmatically created 504
`Response`, so `cacheResponse()` (which checks for `res.ok`) would not
have cached it anyway, but this makes change makes it more explicit (and
more similar to the equivalent part in [handleFetchWithFreshness()][1]).
[1]: https://github.com/angular/angular/blob/2b4d5c754/packages/service-worker/worker/src/data.ts#L379-L388
PR Close#30977