filesystem: Fix CardMF.get_app_names()

This function was not used and doesn't work without this patch.

Change-Id: Id3dad7d97fe29a25792d2f8f0e879666c1d9c136
diff --git a/pySim/filesystem.py b/pySim/filesystem.py
index d52a16e..95f792a 100644
--- a/pySim/filesystem.py
+++ b/pySim/filesystem.py
@@ -384,7 +384,7 @@
 
     def get_app_names(self):
         """Get list of completions (AID names)"""
-        return [x.name for x in self.applications]
+        return list(self.applications.values())
 
     def get_selectables(self, flags=[]) -> dict:
         """Return a dict of {'identifier': File} that is selectable from the current DF.