Texture browser: Don't use file name as menu item label.

Just using the node name is clearer, as it only depends on the node, and
no longer on the linked files themselves. This also makes it easier to
get compatible with HDRi nodes (as those files won't be named
"{name}-{maptype}".

blender_cloud/texture_browser.py

@@ -135,7 +135,7 @@ class MenuItem:
     def node_uuid(self) -> str:
         return self.node['_id']
 
-    def update(self, node, file_desc, thumb_path: str, label_text):
+    def update(self, node, file_desc, thumb_path: str, label_text=None):
         # We can get updated information about our Node, but a MenuItem should
         # always represent one node, and it shouldn't be shared between nodes.
         if self.node_uuid != node['_id']:
@@ -144,6 +144,8 @@ class MenuItem:
         self.node = node
         self.file_desc = file_desc  # pillarsdk.File object, or None if a 'folder' node.
         self.thumb_path = thumb_path
+
+        if label_text is not None:
             self.label_text = label_text
 
     @property
@@ -471,7 +473,7 @@ class BlenderCloudBrowser(pillar.PillarOperatorMixin,
             self.add_menu_item(node, None, 'SPINNER', texture_node['name'])
 
         def thumbnail_loaded(node, file_desc, thumb_path):
-            self.update_menu_item(node, file_desc, thumb_path, file_desc['filename'])
+            self.update_menu_item(node, file_desc, thumb_path)
 
         project_uuid = self.current_path.project_uuid
         node_uuid = self.current_path.node_uuid