Remove fit_columns_model parameter

[amontanez24]

Problem Description

As a user, it is hard to understand what the fit_columns_model parameter does because it forces me to learn about the specific method of how conditional sampling for some constraints is handled.

Expected behavior

• Remove the fit_columns_model parameter
• Move any code related to the columns model into its own columns model class

Additional context

• In constraints.base.py the _validate_constraint_columns method should be changed to just raise the MissingConstraintColumnsError if any columns are missing.
• The _reject_sample and sample_constraint_columns methods can be moved into the columns_model class which can be renamed to something more appropriate.