EuiAvatar does not handle a name composed entirely of whitespace

[legrego]

I noticed this while testing Kibana Spaces. The following crashes the component:

<EuiAvatar name={' '} />

The issue is caused by the code used to derive the avatar initials:

// A. Set to initials prop if exists (but trancate to 2 characters max unless length is supplied)
if (initials) {
  calculatedInitials = initials.substring(0, calculatedInitialsLength);
} else {
  if (name.split(' ').length > 1) {
    // B. If there are any spaces in the name, set to first letter of each word
    calculatedInitials = name.match(/\b(\w)/g).join('').substring(0, calculatedInitialsLength);
  } else {
    // C. Set to the name's initials truncated based on calculated length
    calculatedInitials = name.substring(0, calculatedInitialsLength);
  }
}

This condition fails in step "B" above, because the regular expression /\b(\w)/g returns null for a string composed entirely of whitespace.

For this scenario, I'd expect the initials to be calculated as an empty string. Granted, this ins't a common scenario, and likely not one we want to encourage in a UI, but we should at least make sure the component doesn't crash.