Update definition.json

Adding the multiple possibility for SMSC GT to cover SMS Spaming case. Also text field for multiple details if needed.
Adding "MapSmsText" attribute to help matching malicious URL, keywords or MSISDN inside SMS.

objects/ss7-attack/definition.json

@@ -111,6 +111,7 @@
     "MapSmscGT": {
       "description": "MAP SMSC. Phone number.",
       "ui-priority": 0,
+      "multiple": true,
       "misp-attribute": "text"
     },
     "MapSmsTP-OA": {
@@ -118,6 +119,11 @@
       "ui-priority": 0,
       "misp-attribute": "text"
     },
+    "MapSmsText": {
+      "description": "MAP SMS Text. Important indicators in SMS text.",
+      "ui-priority": 0,
+      "misp-attribute": "text"
+    },
     "MapSmsTP-PID": {
       "description": "MAP SMS TP-PID.",
       "ui-priority": 0,
@@ -151,6 +157,7 @@
       "description": "A description of the attack seen via SS7 logging.",
       "disable_correlation": true,
       "ui-priority": 0,
+      "multiple": true,
       "misp-attribute": "text"
     },
     "first-seen": {