Prevent the Document Properties from being empty when the dialog is opened before the file has started loading
Remove superfluous 'self' variable from web/document_properties.js
Only update the Document Properties if the dialog is still visible when the dataAvailablePromise is resolved
Merge pull request #4546 from Snuffleupagus/document-properties-wait-for-data

Prevent the Document Properties from being empty when the dialog is opened before the file has started loading