implemented argmax and argmin methods using OpenVINO opset.

[sunny7712]

@rkazants kindly review this. Let me know if there's any changes to be made. Thanks!

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 30 lines in your changes missing coverage. Please review.

Project coverage is 80.12%. Comparing base (d865f5f) to head (28bab0a).
Report is 20 commits behind head on master.

Files with missing lines	Patch %	Lines
keras/src/backend/openvino/numpy.py	0.00%	30 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #21071      +/-   ##
==========================================
- Coverage   82.65%   80.12%   -2.54%     
==========================================
  Files         563      564       +1     
  Lines       53975    54162     +187     
  Branches     8386     8419      +33     
==========================================
- Hits        44615    43396    -1219     
- Misses       7291     8749    +1458     
+ Partials     2069     2017      -52     

Flag	Coverage Δ
keras	79.93% <0.00%> (-2.54%)	⬇️
keras-jax	64.04% <0.00%> (+0.03%)	⬆️
keras-numpy	59.06% <0.00%> (-0.01%)	⬇️
keras-openvino	?
keras-tensorflow	64.33% <0.00%> (-0.01%)	⬇️
keras-torch	64.08% <0.00%> (+0.03%)	⬆️

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[rkazants]

@sunny7712, please fix tests in CI:

FAILED keras/src/ops/numpy_test.py::NumpyOneInputOpsCorrectnessTest::test_argmax - TypeError: topk() missing 1 required positional argument: 'sort'
FAILED keras/src/ops/numpy_test.py::NumpyOneInputOpsCorrectnessTest::test_argmin - TypeError: topk() missing 1 required positional argument: 'sort'
...