[Canvas] Hide global banner list in fullscreen mode (#98058)

Author: cqliu1

x-pack/plugins/canvas/public/components/fullscreen/fullscreen.scss

@@ -19,6 +19,11 @@ body.canvas-isFullscreen {
     display: none;
   }
 
+  // hide global banners
+  #globalBannerList {
+    display: none;
+  }
+
   // set the background color
   .canvasLayout {
     background: $euiColorInk;