Summary:
The rocksdb_block_cache*bytes_read metrics are redundant because their values can be calculated from existing *_hit metrics and known block sizes. They are also considered noisy and less useful because the current implementation increments the metric by the size of the block, not the actual size of the data that was read.

The total bytes read from the block cache is effectively the sum of hits for each block type multiplied by that type's block size:
`Total Bytes Read = (filter_hits * 64KB) + (data_hits * 32KB) + (index_hits * 32KB)`

Removing these metrics reduces noise and overhead.
This change removes the following metrics:
- rocksdb_block_cache_bytes_read
- rocksdb_block_cache_single_touch_bytes_read
- rocksdb_block_cache_multi_touch_bytes_read
Jira: DB-16491

Test Plan: Jenkins

Reviewers: esheng

Reviewed By: esheng

Subscribers: rthallam, ybase, yql

Differential Revision: https://phorge.dev.yugabyte.com/D45737