OHIF-129: Enabling CinePlay button only when active viewport has more than 1 image in its stack; Fixed some errors when CinePlay Dialog is open and stopped and layout changes.

Packages/viewerbase/client/components/viewer/playClipButton/playClipButton.js

@@ -1,5 +1,8 @@
 Template.playClipButton.helpers({
     isPlaying: function() {
         return isPlaying();
+    },
+    disableButton() {
+        return hasMultipleFrames();
     }
 });