Make the DDL checks the same for the command (ddl_api.go) and the execution (ddl_worker.go)

## Enhancement

For checking if a DDL statement is OK, it is first checked in the session of the statement, and then it enters the DDL queue.
When the DDL job is then picked from the queue, it is checked again. These checks are not always the same, and there are cases where some checks are missing in one of them.

This task is to make sure that the checks are the same for both the session and the ddl worker, probably by refactor some checks, so they can be used by both.

Example: ADD PARTITION does checks differently in the DDL Session vs the DDL Worker.