Fix bookmark creation

Bookmarks created in the Nuxeo Enhanced Viewer do not het saved.

How to reproduce:

• create a File document and attach a PDF file to it
• switch to the ANNOTATIONS tab
• in the left panel, click on the Navigate using document structure
• click on the Add a bookmark on the current page icon and enter a name for the bookmark in the input field and press enter. The bookmark gets added to the list of bookmarks
• navigate away e.g. to the parent workspace, then go back to the created File document
• switch to the ANNOTATIONS tab
• in the left panel, click on the Navigate using document structure

Expected result: the previously created bookmark is listed in the bookmark list
Actual result: the previously created bookmark is NOT listed in the bookmark list

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Once the bookmarks are correctly supported, remove the modifications made on NEV-343