Allow calling signal-cli without -u flag

For daemon command all local users will be exposed as dbus objects
If only one local user exists, all other commands will use that user,
otherwise a user has to be specified.

src/main/java/org/asamk/signal/commands/UploadStickerPackCommand.java

@@ -29,7 +29,7 @@ public class UploadStickerPackCommand implements LocalCommand {
             return 3;
         } catch (StickerPackInvalidException e) {
             System.err.println("Invalid sticker pack: " + e.getMessage());
-            return 3;
+            return 1;
         }
     }
 }