[UR][L0] Refactor IL code handling allowing future extension

[Maetveis]

Refactor the code to make it easier to add support for different IL formats (besides SPIR-V) in the future.
The only functional change is that SPIR-V binaries with invalid magic number are now rejected by returning UR_RESULT_ERROR_INVALID_BINARY from urProgramCreateWithIL.

[Maetveis]

I believe the CI failure (https://github.com/intel/llvm/actions/runs/14996606351/job/42133884358 ) is unrelated: #18416

[Maetveis]

I don't believe the CI failure is related:

[ RUN      ] urCommandBufferAppendMemBufferWriteRectTestWithParam.Success/Intel_R__oneAPI_Unified_Runtime_over_Level_Zero_V2__Intel_R__Data_Center_GPU_Max_1100_ID0ID______________________write_3D_with_offsets
Segmentation fault from GPU at 0x8057ffc01000, ctx_id: 1 (CCS) type: 0 (NotPresent), level: 0 (PTE), access: 0 (Read), banned: 1, aborting.
Segmentation fault from GPU at 0x8057ffc01000, ctx_id: 1 (CCS) type: 0 (NotPresent), level: 0 (PTE), access: 0 (Read), banned: 1, aborting.
Abort was called at 276 line in file:
../../neo/shared/source/os_interface/linux/drm_neo.cpp