[Discover] Field list should wrap long field names instead of truncating

[wylieconlon]

There are other issues about making the design of the field list more similar in Discover and Lens, and this is one of the elements that has bothered me the most. The field list in Discover is truncated, making it hard to read the field names:

Compared to Lens, which breaks onto multiple lines on the dots:

The way this works in Lens is that we've implemented a custom function to insert special characters into the title, which will tell browsers to wrap on dots in particular:

function wrapOnDot(str?: string) {
  // u200B is a non-width white-space character, which allows
  // the browser to efficiently word-wrap right after the dot
  // without us having to draw a lot of extra DOM elements, etc
  return str ? str.replace(/\./g, '.\u200B') : '';
}

Related issues: #68206

cc @kertal

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)

[kertal]

cc @andreadelrio