Find the phone numbers of customers using the most common policy type among the available policies.
SELECT customer_phone FROM available_policies WHERE policy_type_code  =  (SELECT policy_type_code FROM available_policies GROUP BY policy_type_code ORDER BY count(*) DESC LIMIT 1)
Mevcut politikalar arasında en yaygın politika türünü kullanan müşterilerin telefon numaralarını bulun.