[NPU] Add EliminateIdentity pass before IR serialize (#33166)
### Details:
- *Eliminates `Identity` ops in NPU plugin before passing the serialized
model to the NPU driver.*
- *WIP*
### Tickets:
- *CVS-177222*
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Signed-off-by: Stefania Hergane <stefania-persida.hergane@intel.com>
Co-authored-by: Mircea-Aurelian Dan <mircea-aurelian.dan@intel.com>
