Delete queue_on_two_stacks.py which duplicates queue_by_two_stacks.py (#8624)

* Delete queue_on_two_stacks.py which duplicates queue_by_two_stacks.py

* updating DIRECTORY.md

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Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>

Author: cclauss

DIRECTORY.md

@@ -232,6 +232,7 @@
     * [Double Ended Queue](data_structures/queue/double_ended_queue.py)
     * [Linked Queue](data_structures/queue/linked_queue.py)
     * [Priority Queue Using List](data_structures/queue/priority_queue_using_list.py)
+    * [Queue By Two Stacks](data_structures/queue/queue_by_two_stacks.py)
     * [Queue On List](data_structures/queue/queue_on_list.py)
     * [Queue On Pseudo Stack](data_structures/queue/queue_on_pseudo_stack.py)
   * Stacks