Use screen name in Topnav, unicode truncate in-browser

[mc2]

WEBDEV-5735

Description

• Uses screen name for user icon alt= and user string in top nav
• Uses in-browser truncation
• Fixed and added screen name truncation tests to demo
• Handles RTL language screen names

Technical

• in-code string truncation removed

Testing

• Try to break truncation of unicode using multi-code point characters (ex. family with kids) and lengthening max-width in browser inspector.
• Try to break with XSS screen names
• QA: Is the max-width the right width?

Evidence