Fix empty layoutAssignments

Sometimes layout assigments come empty like this `<layoutAssignments><!-- 1 children --></layoutAssignments>`.
We need to check if the `recordType` element exists before accessing it.

Author: naicigam

cumulusci/tasks/salesforce/update_profile.py

@@ -288,9 +288,11 @@ def _set_record_types(self, tree, api_name):
                 # Look for page layout definitions in the record type
                 found_layout = False
                 for elem in tree.findall("layoutAssignments"):
-                    if elem.find("recordType").text == rt["record_type"]:
-                        elem.layout.text = layout_option
-                        found_layout = True
+                    record_type_elem = elem.find("recordType")
+                    if record_type_elem:
+                        if record_type_elem.text == rt["record_type"]:
+                            elem.layout.text = layout_option
+                            found_layout = True
 
                 if not found_layout:
                     assignment = tree.append(tag="layoutAssignments")