[ticket/13033] Fix "Duplicate entry 'notification.type.*' for key 'type'"

Caused by the solution of PHPBB3-12990

PHPBB3-13033
[ticket/12368] Always clean the cache prior to run the migrations

PHPBB3-12368
Merge pull request #3017 from nickvergessen/ticket/13033

[ticket/13033] Fix "Duplicate entry 'notification.type.*' for key 'type'"