Revert "Added validation is check isMutating() before saving the file"

This reverts commit e588d51.

src/seedu/addressbook/logic/Logic.java

@@ -85,10 +85,7 @@ public CommandResult execute(String userCommandText) throws Exception {
     private CommandResult execute(Command command) throws Exception {
         command.setData(addressBook, lastShownList);
         CommandResult result = command.execute();
-        if (command.isMutating()) {
-        	 storage.save(addressBook);
-
-        }
+        storage.save(addressBook);
         return result;
     }