samples: add list buckets with partial success sample

[nidhiii-27]

This PR adds a new code sample to demonstrate how to list buckets with partial success. This is based on the feature introduced in #3415.

[snippet-bot]

Here is the summary of changes.

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• samples/snippets/src/main/java/com/example/storage/bucket/ListBucketsWithPartialSuccess.java:19, tag storage_list_buckets_with_partial_success

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