Hide the textfield when not enable.

client/coral-admin/src/containers/Configure.css

@@ -61,3 +61,7 @@
   font-size: 14px;
   letter-spacing: 0.03em;
 }
+
+.hidden {
+  display: none;
+}

client/coral-admin/src/containers/Configure.js

@@ -72,7 +72,7 @@ class Configure extends React.Component {
         Write a message to be added to the top of your comment stream. Pose a topic, include community guidelines, etc.
         </ListItemContent>
       </ListItem>
-      <ListItem className={styles.configSettingInfoBox}>
+      <ListItem className={`${styles.configSettingInfoBox} ${this.props.settings.infoBoxEnable ? null : styles.hidden}`} >
         <Textfield
           onChange={this.updateInfoBoxContent}
           value={this.props.settings.infoBoxContent}