[Keras 3 OpenVINO backend] Support gaussian_blur operation

[goyaladitya05]

Request Description

This issue tracks the implementation of the gaussian_blur image operation in the Keras OpenVINO backend. This will help increase the coverage of functional parity for the OpenVINO backend.

I will submit a PR implementing this and enabling the corresponding tests.

Ref: #34017

Feature Use Case

No response

Issue submission checklist

• The feature request or improvement must be related to OpenVINO

[goyaladitya05]

over to you @daehyun99

[daehyun99]

Thanks @goyaladitya05

I will work on this weekend.