Make Remove Command's fields public (#2449)

In #2034, the `Remove` Command did not get the same treatment as the rest of the commands. There's no discussion saying it shouldn't have public fields, so I am assuming it was an oversight. This fixes that oversight.

crates/bevy_ecs/src/system/commands.rs

@@ -359,8 +359,8 @@ where
 
 #[derive(Debug)]
 pub struct Remove<T> {
-    entity: Entity,
-    phantom: PhantomData<T>,
+    pub entity: Entity,
+    pub phantom: PhantomData<T>,
 }
 
 impl<T> Command for Remove<T>