DI provider caches bad bootstrap results

Currently, the implementation of BucketProvider caches Task from the call to Cluster.BucketAsync results for performance. However, this means that if the call fails to bootstrap the erroneous result is returned for the rest of the lifetime of the DI container. We shouldn't cache error results and should retry the call to BucketAsync.

https://forums.couchbase.com/t/how-to-force-a-retry-of-bucketprovider-getbucketasync-without-using-the-cached-bucket-not-found-value-using-dependencyinjection/33594