[client] Adapt indicator testing to use the real attribute name: pattern_type

Author: richard-julien

tests/data/indicator_stix.json

@@ -13,7 +13,7 @@
             "pattern": "[ipv4-addr:value = '103.83.192.6']",
             "valid_from": "2020-04-17T09:50:27.000Z",
             "valid_until": "2021-04-17T09:50:27.000Z",
-            "x_opencti_pattern_type": "stix",
+            "pattern_type": "stix",
             "created": "2020-04-30T06:29:41.232Z",
             "modified": "2020-04-30T06:29:41.232Z",
             "x_opencti_score": 50,
@@ -34,7 +34,7 @@
             "pattern": "[ipv4-addr:value = '192.185.46.253']",
             "valid_from": "2020-04-17T09:50:27.000Z",
             "valid_until": "2021-04-17T09:50:27.000Z",
-            "x_opencti_pattern_type": "stix",
+            "pattern_type": "stix",
             "created": "2020-04-30T06:29:41.303Z",
             "modified": "2020-04-30T06:29:41.303Z",
             "x_opencti_score": 50,