Handle nested bookmarks folder

[darkdh]

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Ran git rebase -i to squash commits (if needed).

fix #4291

Auditors: @bbondy

Test Plan:

1. Create nested folder as Importer should be able to handle nested folder from bookmarks properly #4291 shows
2. Nested folder should be imported correctly

[bbondy]

++