JSON push always wrapped in array structure

#### Description:

I'm working with @enarhi on a workflow that requires JSON output of single objects. Right now as we are still designing the fixed schema, we are working with custom objects. I noticed some unusual behavior when examining the files in a text editor, that the file adapter always wraps everything in an array `[` and `]` regardless of how many objects one is trying to push. This has created some headaches downstream where our read is not expecting an array structure of a single object.

This is also the case when pushing a single BHoM object. The output is always wrapped in an array.