cdc: log: fix use-after-free in process_bytes_visitor
cdc: log: fix use-after-free in process_bytes_visitor

Due to small value optimization used in `bytes`, views to `bytes` stored
in `vector` can be invalidated when the vector resizes, resulting in
use-after-free and data corruption. Fix that.

Fixes #8117

scylladb/scylla,scylladb/scylla,scylladb/scylla,scylladb/scylla