GSM: Make the au key work on string and byte array

GSMDriver.st

@@ -113,7 +113,7 @@ classes.'>
     ]
 
     auKey [
-        ^ phoneConfig auKey.
+        ^ phoneConfig auKeyByteArray.
     ]
 
     imsi [

TestPhone.st

@@ -141,4 +141,20 @@ Object subclass: PhoneConfig [
     auKey: anAuKey [
         auKey := anAuKey.
     ]
+
+    auKeyByteArray [
+        ^ auKey isString
+            ifTrue:  [
+                | array |
+                array := OrderedCollection new.
+                1 to: auKey size by: 2 do: [:each |
+                    array add: (Number readFrom:
+                                    (auKey copyFrom: each to: each + 1) readStream
+                                    radix: 16)
+                ].
+
+                array asByteArray.
+            ]
+            ifFalse: [auKey].
+    ]
 ]