Shorten description help text

Currently it word wraps, this prevents word-wrapping

web/react/components/new_channel_modal.jsx

@@ -150,7 +150,7 @@ export default class NewChannelModal extends React.Component {
                                         tabIndex='2'
                                     />
                                     <p className='input__help'>
-                                        {'This is the purpose of your channel and helps others decide whether to join.'}
+                                        {'Channel description helps others decide whether to join.'}
                                     </p>
                                     {serverError}
                                 </div>