Add doctest for circular queue overflow condition (#13590)

* Add doctest for circular queue overflow condition

Added a doctest to test the QUEUE IS FULL exception when attempting to enqueue an element into a full circular queue. This improves test coverage for line 67 in data_structures/queues/circular_queue.py.

Fixes #9943

* Update circular_queue.py

* Update circular_queue.py

* Update circular_queue.py

* Update circular_queue.py

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Co-authored-by: Maxim Smolskiy <[email protected]>