Fix scoped overlay use not finding a module (#6474)

* Add source-env test for dynamic path

* Use correct module ID for env overlay imports

* Remove parser check from "overlay list"

It would cause unnecessary errors from some inner scope if some
overlay module was also defined in some inner scope.

* Restore Cargo.lock back

* Remove comments

crates/nu-protocol/src/ast/call.rs

@@ -82,6 +82,10 @@ impl Call {
         self.positional_iter().nth(i)
     }
 
+    pub fn positional_nth_mut(&mut self, i: usize) -> Option<&mut Expression> {
+        self.positional_iter_mut().nth(i)
+    }
+
     pub fn positional_len(&self) -> usize {
         self.positional_iter().count()
     }