Get rid of unnecessary methods for single table sampling

[amontanez24]

Problem Description

As a developer, it is confusing to have too many methods calling each other if there isn't a good reason.

Expected behavior

• Remove _sample_remaining_columns and _sample_from_conditions and move their contents to the callers. In both cases, the calling just calls them directly passing the same arguments and not adding any other code. It is redundant.