[Bug] Video boolean attributes breaks on import

Explanation Using https://grapesjs.com/demo.html v0.15.8 on Chrome 77.0.3~ Windows 10 Pro Build 18362 Importing a Video component with any Boolean attribute (controls, loop, autoplay) using the import modal will break all boolean attributes on the component until the component is deleted.

Reproduction Steps

• Navigate to https://grapesjs.com/demo.html
• Clear the canvas
• Drag in a 'Video' Block
• Ensure the 'Controls' boolean attribute is checked (should be by default)
• Open the import code modal
• Click import
• Boolean attribute traits no longer work on the component
• Also can't re-import the video with the boolean attribute removed

Screencast Screencast showing video working as expected, and then the bug.