Summary: When nodes didn't have any metadata, the data was an empty string, which fails json parsing. This causes data be passed to the InspectorSidebarSection as ''. The weak map inside that component expects data to be an object, not a string, and crashes if it's actually a string. This will ensure that data is always an object.
Reviewed By: jknoxville
Differential Revision: D13109384
fbshipit-source-id: 469a1b5c1c00130ef37636bf7c6796b2463fb34b