Add better onerror handling.

It seems like in cases where there is no error on the transaction, a generic AbortError is thrown. However if you inspect the error argument (which is not used) you can actually see the real error that was encountered. This is applicable to the "DataError: Failed to read large IndexedDB value" error

See: https://github.com/jakearchibald/idb/blob/eb2fc14bb3588d09aaa5e86a83bf3519b06e10b3/src/wrap-idb-value.ts#L85-L86

The expectation would be that we should see the real cause, and not swallow it.