Long bookmark folder names should be truncated

[jkup]

• 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 #4739

Auditors: @bradleyrichter @alexwykoff

Test Plan:

We can't just add max-width: 50% because then it'll only take up half the screen when the columns float underneath each other but wrapping it in a breakpoint works.

Add a bookmark folder with a really long name and make sure it looks good with both a huge and small screen.

[alexwykoff]

lgtm, noticed a performance issue of tracking objects while resizing:

i'll open a separate issue for that