[turbopack] Conditionally collect affecting sources (#83921)
The `affecting_sources` field on `ResolveResult` and `ModuleResolveResult` are used for file tracing, but not for normal builds. So make tracking this information conditional.
This will be a minor performance win for a few reasons
* no allocations to store these lists
* no storing this data in the PC database
* changes to affecting sources won't invalidate resolution results.
Closes PACK-5438
