Use the fileViewModel to get the current path

instead of extracting it from the dom

Author: remcoder

octoprint_gcodethumbs/static/js/gcode-preview-viewmodel.js

@@ -88,10 +88,9 @@ $(function() {
     }
 
     function enrichWithPreview(element) {
-        const pathEl = document.querySelector('.back-path [data-bind*=currentPath]');
-        let path = pathEl? pathEl.innerText+'/' : '';
-        if (path == '/') path = '';
-        const filename =  path+extractKey(element);
+      const path = self.filesViewModel.currentPath();
+      const prefix  = path ? path+'/' : '';
+      const filename = prefix + extractKey(element);
 
       if (previews[filename]) {
         insertAfter(previews[filename].canvas, element.querySelector('.title'));