GDScript: Add error when exporting node in non [Node]-derived classes

modules/gdscript/tests/scripts/parser/features/export_variable.gd

@@ -1,3 +1,5 @@
+extends Node
+
 @export var example = 99
 @export_range(0, 100) var example_range = 100
 @export_range(0, 100, 1) var example_range_step = 101
@@ -6,7 +8,8 @@
 @export var color: Color
 @export_color_no_alpha var color_no_alpha: Color
 @export_node_path("Sprite2D", "Sprite3D", "Control", "Node") var nodepath := ^"hello"
-
+@export var node: Node
+@export var node_array: Array[Node]
 
 func test():
 	print(example)
@@ -16,3 +19,5 @@ func test():
 	print(color)
 	print(color_no_alpha)
 	print(nodepath)
+	print(node)
+	print(var_to_str(node_array))

modules/gdscript/tests/scripts/parser/features/export_variable.out

@@ -6,3 +6,5 @@ GDTEST_OK
 (0, 0, 0, 1)
 (0, 0, 0, 1)
 hello
+<null>
+Array[Node]([])