chore: add changelog message

Author: ritvi-alagusankar

changelog/13503.improvement.rst

@@ -0,0 +1,4 @@
+Fixed the order of dictionary keys in assertion failure messages. 
+Previously, dictionary diffs were shown in alphabetical order, regardless of how the keys appeared in the original dicts. 
+Now, common keys are shown in the insertion order of the left-hand dictionary, 
+and differing keys are shown in the insertion order of their respective dictionaries