Evaluate cache strategy before enforcing failure response code

[leesgit]

Summary

Resolves #3391.

NetworkFetcher cached non-2xx responses listed in CACHEABLE_STATUS_CODES (300, 301, 404, 405, 410, 414, 501) to disk, but then unconditionally threw HttpException on the next read before CacheStrategy.read() was invoked. As a result, cache-aware strategies such as CacheControlCacheStrategy could never evaluate whether the cached failure had expired — a cached 404 would throw forever, regardless of Cache-Control headers.

Changes

• Moved throwIfFailureResponseCode(cacheResponse) until after cacheStrategy.read(...) returns a response.
• The check now runs only when the strategy opts to reuse the cached response. When the strategy returns a fresh NetworkRequest instead (e.g. because the cached entry is stale), the fetcher proceeds to the network as expected.

This keeps the existing behavior for CacheStrategy.DEFAULT (which always returns the cached response) and unblocks CacheControlCacheStrategy from honoring expiration on cached failures.

Testing

• ./gradlew :coil-network-core:jvmTest --tests coil3.network.NetworkFetcherTest — all 5 tests pass.
• Existing cached404ResponseThrows still passes (default strategy preserves current behavior).
• New cached404IsRefreshedWhenCacheStrategyRequestsNewRequest verifies that when a strategy returns ReadResult(request), the cached 404 no longer short-circuits with HttpException and the network request is issued.
• ./gradlew :coil-network-core:spotlessCheck — passes.

[colinrtwhite]

Thanks this looks like the proper fix.