(feat) Implement the deprecated ctc_decode function in Keras v3

[lpizzinidev]

What

Implement the deprecated ctc_decode function in keras.losses and make it backend-agnostic.

To achieve this we'll need to implement the following functions in keras.ops.nn:

• tf.nn.ctc_greedy_decoder
• tf.compat.v1.nn.ctc_beam_search_decoder

After the implementation, update the related Automatic Speech Recognition using CTC example on the keras-io repo and make it compatible with all backends, if possible.

Results

• The tf.nn.ctc_greedy_decoder function is implemented in keras.ops.nn with related test coverage
• The tf.compat.v1.nn.ctc_beam_search_decoder function is implemented in keras.ops.nn with related test coverage
• The ctc_decode function is implemented in keras.losses with related test coverage
• The Automatic Speech Recognition using CTC example is updated with the new ctc_decode function and compatible with all backends

[divyashreepathihalli]

@lpizzinidev are you interested in contributing a PR for this issue?

[lpizzinidev]

@divyashreepathihalli
Sure 👍
I'm working on a PR for migrating a keras-io example to v3.
Once that's pushed I'll pick up this one ✅

[fchollet]

This is being implemented in #19366

[sachinprasadhs]

Closing the issue as it is already implemented in the above linked PR.