no-merge: introduce typo to demonstrate assert_equal issue

bitcoin#27380 (comment)

Author: 0xB10C

test/functional/interface_usdt_mempool.py

@@ -315,7 +315,7 @@ def handle_rejected_event(_, data, __):
 
         # expected data
         txid = tx["tx"].hash
-        reason = "min relay fee not met"
+        reason = "min erlay fee not met"
 
         self.log.info("Polling buffer...")
         bpf.perf_buffer_poll(timeout=200)