[Bug] Moving items to "no-variant"-group should empty the group-by field if possible

[Xazin]

Bug Description

I'm not sure if it's the exact desired behavior, but when using the group-by in a Board for example, there's a "no-variant"-group by default, if I drag items to this group, I'd expect that the field that is grouped by, would be emptied if possible for the cards in that group.

How to Reproduce

1. Enable group-by
2. Drag cards with a value in the grouped field to the no-variant group
3. For some field types, the value is not emptied

Expected Behavior

1. Enable group-by
2. Drag cards with a value in the grouped field to the no-variant group
3. For all field types where applicable, the value should be emptied

Operating System

all

AppFlowy Version(s)

0.6.0

Screenshots

No response

Additional Context

No response