Updating the random number generation methods across various files in the cirq-core package to use the newer np.random.Generator instead of the older np.random.RandomState.

One small hack:

1. For random_state.py, directly assigning RandomState._bit_generator could not yield the same result as Generator, even though the RandomState object is created with the same seed; instead I tried to get the RandomState's seed by the following line, and construct from there:

np.random.default_rng(random_state.get_state()[1][0])

Updates to random number generation:

• cirq-core/cirq/contrib/quimb/mps_simulator.py: Changed apply_op and _measure methods to use np.random.Generator instead of np.random.RandomState. Updated the constructor to accept both np.random.Generator and np.random.RandomState.

• cirq-core/cirq/experiments/random_quantum_circuit_generation.py: Updated several methods and constructors to use np.random.Generator instead of np.random.RandomState, including random_rotations_between_two_qubit_circuit, _get_random_combinations, and new_layer.

• cirq-core/cirq/qis/clifford_tableau.py: Updated the _measure method to use np.random.Generator and changed the random number generation method from randint to integers.

• cirq-core/cirq/sim/clifford/clifford_simulator.py: Changed the apply_unitary and apply_measurement methods to use np.random.default_rng and updated the constructor to accept both np.random.Generator and np.random.RandomState.

• cirq-core/cirq/sim/simulation_state.py: Updated the constructor and property methods to use np.random.Generator and provided backward compatibility for np.random.RandomState.