- Add commonStyles.noMarginBottom to the last element of newOverlayContent
- Remove syncOverlayBody__wrapper
- Remove className='syncOverlay'
- Fix sync passphrase selectability
- Fix table width that doesn't make sense
- Replace divs with sections

Test Plan:
1. Open about:preferences#sync
2. Enable Sync
3. Click "Sync a new device"
4. Make sure just padding exists under "Show secret code words"
5. Click "Show secret code words"
6. Make sure the code is selectable