Added openvino backend support for numpy.median (Issue #30115)

[Swaglun]

Added decomposition for numpy.median using OpenVINO backend.

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[codecov-commenter]

Codecov Report

Attention: Patch coverage is 72.05882% with 19 lines in your changes missing coverage. Please review.

Project coverage is 82.66%. Comparing base (e4bca84) to head (d92b60a).

Files with missing lines	Patch %	Lines
keras/src/backend/openvino/numpy.py	72.05%	14 Missing and 5 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #21379      +/-   ##
==========================================
- Coverage   82.67%   82.66%   -0.02%     
==========================================
  Files         565      565              
  Lines       55064    55132      +68     
  Branches     8569     8579      +10     
==========================================
+ Hits        45525    45573      +48     
- Misses       7441     7457      +16     
- Partials     2098     2102       +4     

Flag	Coverage Δ
keras	82.47% <72.05%> (-0.02%)	⬇️
keras-jax	63.42% <0.00%> (-0.08%)	⬇️
keras-numpy	58.60% <0.00%> (-0.08%)	⬇️
keras-openvino	33.51% <72.05%> (+0.05%)	⬆️
keras-tensorflow	63.83% <0.00%> (-0.08%)	⬇️
keras-torch	63.45% <0.00%> (-0.09%)	⬇️

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[Swaglun]

@rkazants PR is ready for review.

Apologies for all the commits, it took me a second to fix my local testing to run on openvino backend on macOS.