remove Labeled supertrait of Trackable

This is no longer needed since 9c6ae1b removed the usages.

Author: teoxoy

wgpu-core/src/resource.rs

@@ -173,7 +173,7 @@ macro_rules! impl_labeled {
     };
 }
 
-pub(crate) trait Trackable: Labeled {
+pub(crate) trait Trackable {
     fn tracker_index(&self) -> TrackerIndex;
 }