Add "format" support for latest JAX.

[cantonios]

The jax.experimental.layout.Format configuration has a "format" attribute rather than a "layout" attribute.

[cantonios]

@hertschuh does this fix the error?

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 4 lines in your changes missing coverage. Please review.

Project coverage is 82.72%. Comparing base (d16424e) to head (4e75805).

Files with missing lines	Patch %	Lines
keras/src/backend/jax/distribution_lib.py	0.00%	3 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #21406      +/-   ##
==========================================
- Coverage   82.73%   82.72%   -0.01%     
==========================================
  Files         565      565              
  Lines       55215    55219       +4     
  Branches     8606     8608       +2     
==========================================
  Hits        45682    45682              
- Misses       7424     7427       +3     
- Partials     2109     2110       +1     

Flag	Coverage Δ
keras	82.53% <0.00%> (-0.01%)	⬇️
keras-jax	63.33% <0.00%> (-0.01%)	⬇️
keras-numpy	58.53% <0.00%> (-0.01%)	⬇️
keras-openvino	33.79% <0.00%> (-0.01%)	⬇️
keras-tensorflow	63.74% <0.00%> (-0.01%)	⬇️
keras-torch	63.37% <0.00%> (-0.01%)	⬇️

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[hertschuh]

Thank you for the PR!