Announcement enters incorrect data types

[ricksburnett]

Describe the bug
Adding a treatment log entry of Event Type Announcement fills protein and fat fields with empty strings.
Schema specifies these fields to be of type number

To Reproduce
Steps to reproduce the behavior:

1. Add Announcement event to log using web interface
2. Query API using api/v3/treatments?sort$desc=date&limit=1&eventType$eq=Announcement

Expected behavior
fat and protein fields should probably not even contain entries for an Announcement. If they need to be filled should be a number. Maybe 0 as default.

Screenshots
[{"enteredBy":"","eventType":"Announcement","reason":"","protein":"","fat":"","duration":0,"notes":"Test","created_at":"2020-04-01T20:40:33.534Z","utcOffset":0,"isAnnouncement":true,"identifier":"5e84fc4161b73397284379f4","srvModified":1585773633534,"srvCreated":1585773633534}]

Your setup information
Nightscout 13.0.1

• What version of Nightscout (e.g. 0.10.3)

Additional context
Causes problems in applications decoding json and expecting fields to have consistent types. Can workaround by getting all treatment not type Announcement and then requesting Announcements without those fields, which aren't really needed, but that's a bit of a pain.