Remove Hidet dependency for server return object

[destefy]

Instead of returning a Hidet CompiledGraph to the client, the server should return a torch.fx.GraphModule.

Here, it returns a GraphModule that simply wraps around the CompiledGraph's compiled forward function. (Note: the GraphModule does NOT trace through the forward function and just treats it like a blackbox. Tracing would probably try to optimize the forward function but hidet's forward function has a dynamic control flow which isn't easily traceable)

The GraphModule's graph looks like:

opcode       name         target       args            kwargs
-----------  -----------  -----------  --------------  --------
placeholder  x            x            ()              {}
call_module  leaf_module  leaf_module  (x,)            {}
output       output       output       (leaf_module,)  {}

It expects all arguments to the forward function it wraps to be passed as a tuple.