[NPU] Remove metadata padding (#35492)
### Details:
- removing metadata padding since it is no longer needed
### Tickets:
- *N/A*
### AI Assistance:
- *AI assistance used: no / yes*
- *If yes, summarize how AI was used and what human validation was
performed (build/tests/manual checks).*
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Signed-off-by: alexandruenache1111 <alexandru.enache@intel.com>
