fix: evaluate derive, maps and switch on read, always before push child

src/derive.luau

@@ -10,8 +10,8 @@ local function derive<T>(source: () -> T): () -> T
     evaluate_node(node)
 
     return function()
-        push_child_to_scope(node)
         evaluate_node(node)
+        push_child_to_scope(node)
         return node.cache
     end
 end

src/maps.luau

@@ -209,6 +209,7 @@ local function values<K, VI, VO>(input: () -> Map<K, VI>, transform: (VI, () ->
     evaluate_node(node)
 
     return function()
+        evaluate_node(node)
         push_child_to_scope(node)
         return node.cache
     end

src/switch.luau

@@ -53,6 +53,7 @@ local function switch<T, U>(source: () -> T): (map: Map<T, ((() -> U)?)>) -> ()
         evaluate_node(node)
 
         return function()
+            evaluate_node(node)
             push_child_to_scope(node)
             return node.cache
         end