message: fix CollaborativeInput
  Backspace is broken in CollaborativeInput if you are not at the very end.
  This was because string.substring(start,end) will swap the numbers if end < start. This bug was already fixed in CollaborativeText so I ported the code from there.
diff: @@ -89,9 +89,10 @@ export class CollaborativeInput extends React.Component<IProps, IState> {
  // Get the new caret position and use that to get the text that was inserted
  const newPosition = ev.currentTarget.selectionStart ? ev.currentTarget.selectionStart : 0;
  + const isTextInserted = newPosition - this.state.selectionStart > 0;
  + if (isTextInserted) {
  const insertedText = newText.substring(this.state.selectionStart, newPosition);
  const changeRangeLength = this.state.selectionEnd - this.state.selectionStart;
  - if (insertedText) {
  if (changeRangeLength === 0) {
  this.props.sharedString.insertText(this.state.selectionStart, insertedText);
  } else {
  