Add back the unsigned.age property to voip event examples

event-schemas/examples/m.call.answer

@@ -9,5 +9,8 @@
       "type" : "answer",
       "sdp" : "v=0\r\no=- 6584580628695956864 2 IN IP4 127.0.0.1[...]"
     }
+  },
+  "unsigned": {
+    "age": 1234,
   }
 }

event-schemas/examples/m.call.candidates

@@ -11,5 +11,8 @@
         "candidate": "candidate:863018703 1 udp 2122260223 10.9.64.156 43670 typ host generation 0"
       }
     ]
+  },
+  "unsigned": {
+    "age": 1234,
   }
 }

event-schemas/examples/m.call.hangup

@@ -4,5 +4,8 @@
   "content": {
     "version" : 0,
     "call_id": "12345"
+  },
+  "unsigned": {
+    "age": 1234,
   }
 }

event-schemas/examples/m.call.invite

@@ -9,5 +9,8 @@
       "type" : "offer",
       "sdp" : "v=0\r\no=- 6584580628695956864 2 IN IP4 127.0.0.1[...]"
     }
+  },
+  "unsigned": {
+    "age": 1234,
   }
 }