[Keras 3 OpenVINO Backend]: Support numpy.prod operation

[Imokutmfon]

Implementation of numpy.prod on Keras Openvino Backend

Fixes openvinotoolkit/openvino#30212

please review @rkazants

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 84.00000% with 4 lines in your changes missing coverage. Please review.

Project coverage is 82.72%. Comparing base (be9b002) to head (f1d10c5).

Files with missing lines	Patch %	Lines
keras/src/backend/openvino/numpy.py	84.00%	3 Missing and 1 partial ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #21405   +/-   ##
=======================================
  Coverage   82.72%   82.72%           
=======================================
  Files         565      565           
  Lines       55219    55244   +25     
  Branches     8608     8614    +6     
=======================================
+ Hits        45682    45703   +21     
- Misses       7427     7430    +3     
- Partials     2110     2111    +1     

Flag	Coverage Δ
keras	82.53% <84.00%> (+<0.01%)	⬆️
keras-jax	63.31% <0.00%> (-0.03%)	⬇️
keras-numpy	58.50% <0.00%> (-0.03%)	⬇️
keras-openvino	33.83% <84.00%> (+0.03%)	⬆️
keras-tensorflow	63.71% <0.00%> (-0.03%)	⬇️
keras-torch	63.34% <0.00%> (-0.03%)	⬇️

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