fix: hasOwnProperty is not a function issue from json-big

[jczhong84]

Issue
The json column transformer somehow didn't work with error

Uncaught TypeError: e.hasOwnProperty is not a function
    at vendors-node_modules_lodash_sampleSize_js-node_modules_react-json-view_dist_main_js.1fa9e63d206dc9b137e1.js:209:107637
    at Array.forEach (<anonymous>)
    at a.renderObjectContents (vendors-node_modules_lodash_sampleSize_js-node_modules_react-json-view_dist_main_js.1fa9e63d206dc9b137e1.js:209:107544)

Cause
The parsed json object doesn't has functions like hasOwnProperty from the Object prototype.

Fix
As a workaround, we'll use object spread to copy the parsed json over to a plain Javascript object.