refactor(turborepo): Changed cache misses to be a non-error (#6369)
### Description
Originally we had cache misses be an error. That was a mistake because
it was too easy to propagate a cache miss up the stack and not handle it
properly. It was also too easy to not convert the error into a cache
miss. Now we have a `CacheResult` type that indicates either a miss or a
hit.
### Testing Instructions
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Closes TURBO-1585
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Co-authored-by: nicholaslyang <Nicholas Yang>
Co-authored-by: Chris Olszewski <chris.olszewski@vercel.com>