Fixed drag crashing for streamfiles

[sebjulliand]

Changes

This fixes an issue preventing streamfiles from being dragged and dropped from the IFS browser.
Dragging a streamfile would trigger the following error, shown in the developer console:

That happened during the item JSON serialization finding a circular reference (i.e. IFSFileItem's command would reference this, which indeed creates a circular reference).

To fix this, the command won't reference this anymore but only the required field to call the command (i.e. this.path).

The same fix has been applied on ObjectBrowserMemberItem to prevent the same problem in case it gets serialized.

How to test this PR

1. Confirm drag'n'drop fails for a single streamfile without the PR (checkout the developer console to confirm the error)
2. Checkout the PR
3. Confirm drag'n'drop succeeds for a single streamfile
4. Opening a streamfile for browse/edit must work
5. Opening a source member for browse/edit must work

Checklist

• have tested my change

[chrjorgensen]

@sebjulliand Drag and drop of streamfiles works now - also into the editor space.

I'm not sure what you mean by

Opening a streamfile for browse/edit must work
Opening a source member for browse/edit must work

Streamfiles can be opened by dragging or clicking.
Members can only be opened by clicking. Isn't that enough?

[sebjulliand]

@chrjorgensen it's just to be safe, because I made a change on the command call bound to the ifs file item and source member item.

[chrjorgensen]

Understood. Approved and merged. 👍