Add augment_bounding_boxes support to AugMix layer

[divyashreepathihalli]

The augment_bounding_boxes should be implemented for AugMix Layer in keras_cv. The PR should contain implementation, test scripts and a demo script to verify implementation.

Example code for implementing augment_bounding_boxes() can be found here

• https://github.com/keras-team/keras-cv/blob/master/keras_cv/layers/preprocessing/random_flip.py#:~:text=def%20augment_bounding_boxes(,)%3A
• https://github.com/keras-team/keras-cv/blob/master/keras_cv/layers/preprocessing/random_rotation.py#:~:text=def%20augment_image(self%2C%20image%2C%20transformation%2C%20**kwargs)%3A
• The implementations can be verified using demo utils in keras_cv.bounding_box - Example of demo script can be found here : https://github.com/keras-team/keras-cv/blob/master/examples/layers/preprocessing/bounding_box/random_rotation_demo.py

[LukeWood]

Infeasible