Fix result parsing of "suspend_uicc"

prior to this patch, the suspend_uicc command would always cause a
python exception as a list of integers was returned by decode_duration rather than a single integer (that can be used with %u format string).

Change-Id: I981e9d46607193176b28cb574564e6da546501ba
diff --git a/pySim/commands.py b/pySim/commands.py
index b0f8b39..6acdb2e 100644
--- a/pySim/commands.py
+++ b/pySim/commands.py
@@ -610,7 +610,7 @@
 
         def decode_duration(enc: Hexstr) -> int:
             time_unit = enc[:2]
-            length = h2i(enc[2:4])
+            length = h2i(enc[2:4])[0]
             if time_unit == '04':
                 return length * 10*24*60*60
             elif time_unit == '03':