LossScaleOptimizer#get_scaled_loss() does not exist
Hi **@keisen** ,

I tried to run your code on colab using TF v2.15, 2.16 and nightly versions, and faced the same issue. Please find the [gist ](https://colab.sandbox.google.com/gist/Venkat6871/0b7dc2e7d692a41f7859030e0b0cd169/64124_2-15-2-16-nightly-v.ipynb)here for reference.

Thank you! Hi @Venkat6871 

Thank you for reproducing this issue. I believe it's the same as I faced.
My OSS library has been using this API, so I want your team to fix it asap...
When do you expect it to be fixed?

Thanks! Hi @Venkat6871 
Is there any progress? @Venkat6871 

The same issue:
    scaled_loss = self.optimizer.get_scaled_loss(loss)
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'LossScaleOptimizer' object has no attribute 'get_scaled_loss'

But it's here defined: https://github.com/tensorflow/tensorflow/blob/master/tensorflow/python/keras/mixed_precision/loss_scale_optimizer.py#L524
 @keisen @Venkat6871 
Please look at this solution:
https://github.com/keras-team/keras/issues/19479 @markub3327 

Thank you so much for letting us know that!
I'll close this issue 👍 

Thanks! Are you satisfied with the resolution of your issue?
<a href="https://docs.google.com/forms/d/e/1FAIpQLSfaP12TRhd9xSxjXZjcZFNXPGk4kc1-qMdv3gc6bEP90vY1ew/viewform?entry.85265664=Yes&entry.2137816233=https://github.com/tensorflow/tensorflow/issues/64124">Yes</a>
<a href="https://docs.google.com/forms/d/e/1FAIpQLSfaP12TRhd9xSxjXZjcZFNXPGk4kc1-qMdv3gc6bEP90vY1ew/viewform?entry.85265664=No&entry.2137816233=https://github.com/tensorflow/tensorflow/issues/64124">No</a>

### Issue type

Bug

### Have you reproduced the bug with TensorFlow Nightly?

Yes

### Source

binary

### TensorFlow version

tf2.16+

### Custom code

No

### OS platform and distribution

Linux Ubuntu 20.04 on Windows10 WSL

### Mobile device

_No response_

### Python version

3.10.13

### Bazel version

_No response_

### GCC/compiler version

_No response_

### CUDA/cuDNN version

_No response_

### GPU model and memory

_No response_

### Current behavior?

As this title says, `LossScaleOptimizer#get_scaled_loss()` method does NOT exist.
Until tf2.15, the method definitely existed.
Where is it now? or How do we access it?

[https://www.tensorflow.org/api_docs/python/tf/keras/mixed_precision/LossScaleOptimizer](https://www.tensorflow.org/api_docs/python/tf/keras/mixed_precision/LossScaleOptimizer?_gl=1*1kcgzin*_up*MQ..*_ga*MTU5OTYzMDg2MS4xNzExMDAwMDg0*_ga_W0YLR4190T*MTcxMTAwMDA4My4xLjAuMTcxMTAwMDA4My4wLjAuMA..#get_scaled_loss)

### Standalone code to reproduce the issue

```shell
import tensorflow as tf

optimizer = tf.optimizers.Adam()
wrapped_optimizer = tf.keras.mixed_precision.LossScaleOptimizer(optimizer)

print(f'get_scaled_loss() exists: {"get_scaled_loss" in dir(wrapped_optimizer)}')
```


### Relevant log output

```shell
get_scaled_loss() exists: False
```
