Updates user model to have correct number types

These values were copied down as numbers instead of integers. This
creates issues with some languages which will treat them as floats.

api.json

@@ -1,7 +1,7 @@
 {
   "openapi": "3.0.0",
   "info": {
-    "version": "1.2.2",
+    "version": "1.2.3",
     "title": "OneSignal",
     "description": "A powerful way to send personalized messages at scale and build effective customer engagement strategies. Learn more at onesignal.com",
     "contact": {
@@ -1757,10 +1757,10 @@
             "type": "string"
           },
           "first_active": {
-            "type": "number"
+            "type": "integer"
           },
           "last_active": {
-            "type": "number"
+            "type": "integer"
           },
           "amount_spent": {
             "type": "number"
@@ -1780,10 +1780,10 @@
         "type": "object",
         "properties": {
           "session_time": {
-            "type": "number"
+            "type": "integer"
           },
           "session_count": {
-            "type": "number"
+            "type": "integer"
           },
           "purchases": {
             "type": "array",
@@ -1824,13 +1824,13 @@
             "type": "boolean"
           },
           "notification_types": {
-            "type": "number"
+            "type": "integer"
           },
           "session_time": {
-            "type": "number"
+            "type": "integer"
           },
           "session_count": {
-            "type": "number"
+            "type": "integer"
           },
           "sdk": {
             "type": "string"
@@ -1845,7 +1845,7 @@
             "type": "boolean"
           },
           "test_type": {
-            "type": "number"
+            "type": "integer"
           },
           "app_version": {
             "type": "string"