esim.es2p: Permit ApiParamInteger to be an actual integer

Usually, the specifications say that the integer type is actually
transmitted as a JSON string type.  However, it seems some
implementations do return a native JSON integer type.  Let's be
tolerant in that regard.

Change-Id: I5b47f8bba01225d53eff2ca086e53a2133abed7f

pySim/esim/es2p.py

@@ -86,6 +86,8 @@ class ApiParamInteger(ApiParam):
 
     @classmethod
     def verify_encoded(cls, data):
+        if isinstance(data, int):
+            return
         if not data.isdecimal():
             raise ValueError('integer (%s) contains non-decimal characters' % data)
         assert str(int(data)) == data