[CodeGen] Fix: Address JSON field naming and extension capture in vk_parser codegen.

Key Updates:
- Corrects JSON field naming for the extension struct template.
- Ensures extensions with common structures are correctly captured.
- Added updated vkjson* and vk.py files

Bug: N/A
Test: adb shell cmd gpu vkjson
Flag: NONE infeasible
Change-Id: Id4acb0e60a174cc9023c71b83cd61893cd5bf82b