No network connection error message shown when trying to sync offline but enable sync

[srirambv]

Did you search for similar issues before submitting this one? Yes

Description: No network connection error message shown when trying to sync offline

Device (iPhone5, iPhone6s plus, iPad 3, ?): iPhone 7+ (iOS 10.3.3) - Pyramid 1 iPhone 6 (iOS 10.3.3) - Pyramid 0

Brave Version: 1.4(17.06.15.13)

Steps to reproduce: 1. Enable Sync on device 1(iPhone 6) which is connected to internet 2. On device 2(iPhone 7+) disconnect from internet and type in the code words shown on device 1(iPhone 6) 3. Sync loading spinner is shown for ~40 seconds and then goes back to Enter code words screen, No network error message is shown 4. Tap on Sync button, Goes back to sync main menu and shows the sync is enabled

Actual Behavior No network connection error message shown when trying to sync offline but enable sync

Expected Behavior Should show network error message and should not sync

Is this an issue with Beta build? Yes

Is this an issue in the currently released version? N/A

Can this issue be consistently reproduced? Yes

Extra QA steps: 1. 2. 3.

Screenshot if needed:

Any related issues: cc: @ayumi @diracdeltas @jamesmudgett