`get_layout_map()` is not documented for Llama backbone

[yufengg]

Describe the bug
get_layout_map() is available in both Gemma and Llama backbones. But in the docs, the Llama method is not listed. I think it belongs on this page: https://keras.io/keras_hub/api/models/llama/llama_backbone/

Method implementation is here: https://github.com/keras-team/keras-hub/blob/master/keras_hub/src/models/llama/llama_backbone.py#L213

Corresponding Gemma doc for ref: https://keras.io/keras_hub/api/models/gemma/gemma_backbone/#getlayoutmap-method

To Reproduce
Go to https://keras.io/keras_hub/api/models/llama/llama_backbone/ , observe that get_layout_map() is not documented.

Expected behavior
get_layout_map() should be documented, since it is available: https://github.com/keras-team/keras-hub/blob/master/keras_hub/src/models/llama/llama_backbone.py#L213