More human friendly "show tables" output for db cleanup

[jedcunningham]

Don't print the string representation of a list, print out just the table names.

Before:

You have requested that we drop 4 archived tables prefixed with _airflow_deleted__.
This is irreversible. Consider backing up the tables first Show tables? (y/n): y ['_airflow_deleted__dag__20240401153649', '_airflow_deleted__dag_run__20240401153649', '_airflow_deleted__job__20240401153649', '_airflow_deleted__log__20240401153649'] 

After:

You have requested that we drop 4 archived tables prefixed with _airflow_deleted__.
This is irreversible. Consider backing up the tables first.
Show tables that will be dropped? (y/n): y
_airflow_deleted__dag__20240401153649
_airflow_deleted__dag_run__20240401153649
_airflow_deleted__job__20240401153649
_airflow_deleted__log__20240401153649

And with less than 3 tables...
Before:

You have requested that we drop the following archived tables ['_airflow_deleted__job__20240401153649', '_airflow_deleted__log__20240401153649'].
This is irreversible. Consider backing up the tables first 

After:

You have requested that we drop the following archived tables: _airflow_deleted__job__20240401153649, _airflow_deleted__log__20240401153649.
This is irreversible. Consider backing up the tables first.