Break up mount hook actions.

app/assets/javascripts/time_tracking_display.js.es6

@@ -46,19 +46,21 @@ function getRandomInt(min, max) {
 
             this.issuable = data;
           },
-        },
-        created() {
-          this.fetchIssuable();
-        },
-        mounted() {
+          subscribeToUpdates() {
             gl.IssuableResource.subscribe(data => this.updateState(data));
-          this.initPolling();
-
+          },
+          listenForSlashCommands() {
             $(document).on('ajax:success', '.gfm-form', (e) => {
               // TODO: check if slash command was updated.
               this.fetchIssuable();
             });
           }
+        },
+        mounted() {
+          this.initPolling();
+          this.subscribeToUpdates();
+          this.listenForSlashCommands();
+        }
       });
     }
   }