[OpenVINO BACKEND] - feat: implement numpy.median for openvino backend

[sudonull-1]

• Fixes : [Good First Issue][Keras 3 OpenVINO Backend]: Support numpy.median operation

• Testing: Currently passsing all tests

CC : @rkazants

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[codecov-commenter]

Codecov Report

Attention: Patch coverage is 91.30435% with 4 lines in your changes missing coverage. Please review.

Project coverage is 82.60%. Comparing base (50dae30) to head (430a2e7).
Report is 17 commits behind head on master.

Files with missing lines	Patch %	Lines
keras/src/backend/openvino/numpy.py	91.30%	2 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #21182      +/-   ##
==========================================
+ Coverage   82.59%   82.60%   +0.01%     
==========================================
  Files         564      564              
  Lines       54407    54448      +41     
  Branches     8449     8466      +17     
==========================================
+ Hits        44936    44978      +42     
+ Misses       7396     7393       -3     
- Partials     2075     2077       +2     

Flag	Coverage Δ
keras	82.41% <91.30%> (+0.01%)	⬆️
keras-jax	63.69% <0.00%> (-0.12%)	⬇️
keras-numpy	58.81% <0.00%> (-0.11%)	⬇️
keras-openvino	33.01% <91.30%> (+0.07%)	⬆️
keras-tensorflow	64.10% <0.00%> (-0.12%)	⬇️
keras-torch	63.78% <0.00%> (-0.12%)	⬇️

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[rkazants]

Please fix tests failures:

Requested output shape [3] is incompatible with input shape
FAILED keras/src/ops/numpy_test.py::NumpyDtypeTest::test_median_int16 - AssertionError: 
- int16
+ float32
FAILED keras/src/ops/numpy_test.py::NumpyDtypeTest::test_median_int32 - AssertionError: 
- int32
+ float32
FAILED keras/src/ops/numpy_test.py::NumpyDtypeTest::test_median_int64 - AssertionError: 
- int64
+ float32
FAILED keras/src/ops/numpy_test.py::NumpyDtypeTest::test_median_int8 - AssertionError: 
- int8
+ float32
FAILED keras/src/ops/numpy_test.py::NumpyDtypeTest::test_median_none - RuntimeError: Check 'backward_compatible_check || in_out_elements_equal' failed at src/core/shape_inference/include/reshape_shape_inference.hpp:370:
While validating node 'opset1::Reshape Reshape_3802654 (opset1::Constant Constant_3802649[0]:f32[], opset8::Gather 
...

[sudonull-1]

@rkazants
Currently passing all the testcases, Code format is failing due to

/opt/hostedtoolcache/Python/3.10.17/x64/lib/python3.10/site-packages/openvino/runtime/init.py:10: DeprecationWarning: The openvino.runtime module is deprecated and will be removed in the 2026.0 release. Please replace openvino.runtime with openvino.