Handle "code 120" errors better when updating profile

[IBBoard]

Describe the bug Twitter's docs say that the 120 code is Account update failed: value is too long (maximum is nn characters). but I just got Account update failed: Name can't include "invalid characters".

We need to a) actually error when an update happens and b) separate out the 120 codes and assume "Account update failed:" is a prefix for the real problem.

To Reproduce Steps to reproduce the behavior:

1. Click the accounts button (top-left)
2. Click a cog on an account to open account settings
3. Change username to include "<"
4. Save
5. Dialog closes and Utils.vala:216: Exception tweet-action:120: Account update failed: Name can't include "invalid characters". is logged at command prompt

Expected behavior Error appears and is translated properly for different sub-errors