Fix nuxeo-document-tree displaying long titles with large number of nested folders

nuxeo-document-tree doesn't account for large numbers of nested folders with long titles, resulting in innermost folder names taking large amounts of vertical space.

Steps to reproduce:
1. In Web UI, create 10-15+ nested folderish Documents.
2. Click the Browse icon in the drawer to display the nuxeo-document-tree.
3. Click the caret icon to expand nested folders. Observe title displays past approximately ten nested folders.

Expected behavior: displays of long titles are limited (for example, to two lines with ellipses, or to one line while allowing scrolling to see full titles) to allow for large numbers of nested folders.

Actual behavior: past 10-15 nested folders, titles take up multiple lines and large amounts of vertical space. (see attached image/video for reference)