Base tables that use compact storage may have a special artificial column that has an empty type.c010cefc4dfixed the main CDC path to handle such columns correctly and to not include them in the CDC Log schema. This patch makes sure that generation of preimage ignores such empty column as well. Fixes #9876 Closes #9910 Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com> (cherry picked from commit09d4438a0d)