Simplify transition code

client/coral-embed-stream/src/components/Comment.js

@@ -112,10 +112,6 @@ class Comment extends React.Component {
     }
   }
 
-  componentWillAppear(callback) {
-    callback();
-  }
-
   componentWillEnter(callback) {
     callback();
     const userId = this.props.currentUser ? this.props.currentUser.id : null;
@@ -132,10 +128,6 @@ class Comment extends React.Component {
     this.setState({animateEnter: true});
   }
 
-  componentWillLeave(callback) {
-    callback();
-  }
-
   static propTypes = {
     reactKey: PropTypes.string.isRequired,