[Analytics] Fix bulk reads of multiple tables that potentially have the same data file name

When reading multiple data frames using bulk reader from different tables, it is possible to encounter a data file name being retrieved from the same Sidecar instance. Because the SSTable}}s are cached in the {{SSTableCache, it is possible that the org.apache.cassandra.spark.reader.SSTableReader is using the incorrect SSTable if it was cached with the same #hashCode.