[OpenVINO backend] Remove usage of deprecated openvino.runtime

[p-wysocki]

openvino.runtime is deprecated in favor of flat openvino and is set to be removed in the upcoming OpenVINO release.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 82.76%. Comparing base (e233825) to head (8da66fc).

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #21418      +/-   ##
==========================================
- Coverage   82.76%   82.76%   -0.01%     
==========================================
  Files         565      565              
  Lines       55378    55375       -3     
  Branches     8646     8646              
==========================================
- Hits        45833    45830       -3     
  Misses       7442     7442              
  Partials     2103     2103              

Flag	Coverage Δ
keras	82.57% <100.00%> (-0.01%)	⬇️
keras-jax	63.34% <0.00%> (+<0.01%)	⬆️
keras-numpy	58.53% <0.00%> (+<0.01%)	⬆️
keras-openvino	33.76% <100.00%> (-0.01%)	⬇️
keras-tensorflow	63.78% <0.00%> (+<0.01%)	⬆️
keras-torch	63.39% <0.00%> (+<0.01%)	⬆️

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[rkazants]

do NOT merge, openvino test is failing

[p-wysocki]

@fchollet @mattdangerw The CI is failing with pre-commit check api-gen, but there's no explicit error message. I ran the generation script as instructed in https://github.com/keras-team/keras?tab=readme-ov-file#minimal-installation with .shell/api_gen.sh, but it updated ~130 files with changes which are irrelevant, for example:

diff --git a/keras/api/optimizers/__init__.py b/keras/api/optimizers/__init__.py
index 40f6ab401..4114fab5b 100644
--- a/keras/api/optimizers/__init__.py
+++ b/keras/api/optimizers/__init__.py
@@ -4,6 +4,7 @@ This file was autogenerated. Do not edit it by hand,
 since your modifications would be overwritten.
 """

+
 from keras.optimizers import legacy as legacy
 from keras.optimizers import schedules as schedules
 from keras.src.optimizers import deserialize as deserialize
@@ -18,9 +19,7 @@ from keras.src.optimizers.adamw import AdamW as AdamW
 from keras.src.optimizers.ftrl import Ftrl as Ftrl
 from keras.src.optimizers.lamb import Lamb as Lamb
 from keras.src.optimizers.lion import Lion as Lion
-from keras.src.optimizers.loss_scale_optimizer import (
-    LossScaleOptimizer as LossScaleOptimizer,
-)
+from keras.src.optimizers.loss_scale_optimizer import LossScaleOptimizer as LossScaleOptimizer
 from keras.src.optimizers.muon import Muon as Muon

Is this expected? @rkazants suggested that it may be caused by wrong ordering of imports in my PR, but I changed it in numerous different ways and the check still fails.