/api/v1/notifications: invalid input value for enum notification_type: "poll"

Environment

• Installation type: From source
• Pleroma version (could be found in the "Version" tab of settings in Pleroma-FE): 122328b9

Bug description

Fetching /api/v1/notifications?limit=30&exclude_types%5B%5D=favourite&exclude_types%5B%5D=poll&exclude_types%5B%5D=reblog would throw an exception, cited in issue title, effectively breaking clients.

Assosiated issue in Tusky bugtracker with Pleroma log: https://github.com/tuskyapp/Tusky/issues/1830