Fix 'Activity' tab showing unwanted activity

When navigating to the parent folderish of a document, a download activity is reported in the activities of the child document, corresponding to the download of the thumbnail rendition for the listing of the parent folderish document.

How to reproduce:

• create a workspace
• import an image in it
• check the document's history: 2 audit log entries created:
• document created
• download view empty_picture.png
• check document's Activity tab in metadata sidebar:
• created the document
• viewed the document
• navigate to parent workspace
• navigate back to the Picture document
• 4 audit log entries in the document's history

Expected result: 3 activities in the document's Activity tab: created the document, viewed the document (document was viewed and thumbnail was viewed in the documents listing, these activities are regrouped), downloaded the document (document was explicitly downloaded through the download button)
Actual result: 4 activities in the document's Activity tab: created the document, viewed the document, downloaded the document, downloaded the document (download of rendition `thumbnail` when parent workspace was listed, should be a view instead)