GDScript: Improve call analysis

* Add missing `UNSAFE_CALL_ARGUMENT` warning.
* Fix `Object` constructor.
* Display an error for non-existent static methods.

modules/gdscript/tests/scripts/runtime/features/object_constructor.gd

@@ -0,0 +1,6 @@
+# GH-73213
+
+func test():
+	var object := Object.new() # Not `Object()`.
+	print(object.get_class())
+	object.free()