fix: doc.get_title should return empty string if title is not set

(cherry picked from commit b244c91)

frappe/model/document.py

@@ -472,7 +472,7 @@ def set_new_name(self, force=False, set_name=None, set_child_names=True):
 
 	def get_title(self):
 		"""Get the document title based on title_field or `title` or `name`"""
-		return self.get(self.meta.get_title_field())
+		return self.get(self.meta.get_title_field()) or ""
 
 	def set_title_field(self):
 		"""Set title field based on template"""