[BUG] S3RetryingInputStream incorrectly parses Content-Range value

[andrross]

This REGEX is incorrect: https://github.com/opensearch-project/OpenSearch/blob/main/plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/utils/HttpRangeUtils.java#L20

It does not match the "bytes 0-100/200" format specified by RFC 9110.

The result is that readBlob(String, long, long) is broken, and searchable snapshots is therefore broken.

We are also missing coverage of this API in https://github.com/opensearch-project/OpenSearch/blob/main/test/framework/src/main/java/org/opensearch/repositories/blobstore/OpenSearchBlobStoreRepositoryIntegTestCase.java

Related #9125

[andrross]

I actually think this bug can manifest in the readBlob(String) method as well, because under the hood the S3RetryingInputStream can attempt to open a range after a failure part way through reading the stream (that's the "retrying" part). This would result in the long overflow error during the snapshot restore path.