Provide a way to get a pointer to the GPU memory for the final state vector

### Is your feature request related to a use case or problem?

From personal communication with @s-mandra: his group would benefit from having the possibility of getting a pointer to the GPU memory when calling `simulator.simulate(...).final_state_vector`.

### What solution or approach do you envision?

_No response_

### How urgent is this for you?

P2 – needed within two quarters