fix: curry getProjectThumbnail

Author: KManolov3

packages/scratch-gui/src/components/stage-header/stage-header.jsx

@@ -45,7 +45,7 @@ const messages = defineMessages({
     },
     setThumbnail: {
         defaultMessage: 'Set Thumbnail',
-        description: 'Manually save project thumbnail   ',
+        description: 'Manually save project thumbnail',
         id: 'gui.stageHeader.saveThumbnail'
     },
     fullscreenControl: {

packages/scratch-gui/src/lib/project-saver-hoc.jsx

@@ -61,7 +61,7 @@ const ProjectSaverHOC = function (WrappedComponent) {
             // Allow the GUI consumer to pass in a function to receive a trigger
             // for triggering thumbnail or whole project saves.
             // These functions are called with null on unmount to prevent stale references.
-            this.props.onSetProjectThumbnailer(getProjectThumbnail);
+            this.props.onSetProjectThumbnailer((callback) => getProjectThumbnail(this.props.vm, callback));
             this.props.onSetProjectSaver(this.tryToAutoSave);
         }
         componentDidUpdate (prevProps) {