Update sync common library

[bbondy]

For this:
brave/sync#277

User IDs could be wrong causing bookmarks not to sync because of an encoding problem for slashes. The problem only seems to happen around 1 in every 10 setups. So it would likely be hard to test.
But for QA'ing you can probably just make sure things aren't more broken than before.

[LaurenWags]

Verified passed with

Brave	0.59.35 Chromium: 72.0.3626.81 (Official Build) (64-bit)
Revision	ac8b982e05014492d1bd7d317628a4f22a97ffa0-refs/branch-heads/3626@{#796}
OS	Mac OS X

• Verified several sync scenarios:

• Android-Android (both devices have bookmarks prior to sync chain creation)
• macOS-Android (both devices have bookmarks prior to sync chain creation, after sync chain is created, try adding/moving/deleting a bookmark on each device)
• macOS-Android (macOS had bookmarks prior to sync, but Android was fresh install)
• macOS-Android (Android had bookmarks prior to sync, but macOS was fresh install)
• macOS-Android (neither has bookmarks prior to sync, added bookmarks after sync chain created)