[minor][hotfix] initialize script property in page.py

frappe/core/doctype/page/page.py

@@ -97,6 +97,7 @@ class Page(Document):
 	def load_assets(self):
 		from frappe.modules import get_module_path, scrub
 		import os
+		self.script = ''
 
 		page_name = scrub(self.name)