fix: nbi_cm replace northbound_cm

config/mml_map/http_mml_map.json

@@ -839,7 +839,7 @@
     "end": "(Number of results = %d)\n\n"
 }
 
-"northbound_cm": {
+"nbi_cm": {
     "retFmt": "GetDB",
     "retMsg": "RetCode = %d operation succeeded\n\n",
     "errMsg": "ErrorCode = %d operation failed: %s\n\n",