Fix #1254: Convert pyspiel game state to dict

[Ayah-Saleh]

This pull request introduces the following changes based off issue #1254:

Added ToDict() and FromDict() methods to the State class in spiel.:

• These methods allow converting the game state to a dictionary of array-like structures and restoring the state from such a dictionary.
• ToDict() converts the current state to a dictionary, and FromDict() restores the state from the dictionary representation.

Added a new test case in spiel_test.cc:

• The test verifies that the ToDict() and FromDict() methods work correctly by:
• Converting the state of a Tic-Tac-Toe game to a dictionary.
• Creating a new game state and restoring it using the FromDict() method.
• Making sure that the original and restored states are the same.