bug: Cortex-cpp continues to have 1 layer offload to CPU while using GPU

[Van-QA]

Describe the bug
When generating responses using a local llm, cortex-cpp still seems to use CPU.
https://discord.com/channels/1107178041848909847/1149558035971321886/1253148982188838954

To Reproduce

1. Install cortex-cpp and the CUDA toolkit locally.
2. Turn on GPU acceler‌‌atio‌n
3. Generate responses using a local llm.
4. Observe high CPU usage.

Expected behavior
Since cortex-cpp is using a local llm and the CUDA toolkit, it should primarily use the GPU for processing and not consume as much CPU.

Desktop

• OS: Linux

Additional context
The logs indicate that 32 out of 33 layers are offloaded to the GPU, but 1 layer is still processed on the CPU. This behavior will be investigated further.