Zabbix

A.F....... [ZBX-9414] fixed sorting items and item prototypes by trends

Before the fix:
- items and item prototypes have a default "trends" value of "365", but it is not visible for non-numeric types. This leads to incorrect sorting, filtering and subfiltering.

After the fix:
- items and item prototypes with non-numeric values automatically set "trends" value to zero. The zero value is still not displayed for non-numeric item types, but is now sorted and filtered correctly.