fix: remove all warnings from the kv router merge

[ryanolson]

remove #[allow(dead_code)] from scheduler.rs and fix warnings.

          I put that in there to avoid all the warnings.  This was a quick fix which should have been caught by CI.  CI should enforce the build to complete without errors. This happened on the KV Router merge.  We should open a ticket and resolve those in a separate PR.

Originally posted by @ryanolson in #201 (comment)

[rmccorm4]

warning: field `scheduler` is never read
  --> triton-llm/src/kv_router.rs:48:5
   |
41 | pub struct KvRouter {
   |            -------- field in this struct
...
48 |     scheduler: KvScheduler,
   |     ^^^^^^^^^
   |
   = note: `#[warn(dead_code)]` on by default

warning: variants `NoRoutes` and `SchedulerOffline` are never constructed
  --> triton-llm/src/kv_router/scheduler.rs:33:5
   |
28 | pub enum KvSchedulerError {
   |          ---------------- variants in this enum
...
33 |     NoRoutes,
   |     ^^^^^^^^
...
42 |     SchedulerOffline,
   |     ^^^^^^^^^^^^^^^^
   |
   = note: `KvSchedulerError` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis

warning: field `request_tx` is never read
  --> triton-llm/src/kv_router/scheduler.rs:90:5
   |
89 | pub struct KvScheduler {
   |            ----------- field in this struct
90 |     request_tx: tokio::sync::mpsc::Sender<SchedulingRequest>,
   |     ^^^^^^^^^^

warning: method `schedule` is never used
   --> triton-llm/src/kv_router/scheduler.rs:178:18
    |
93  | impl KvScheduler {
    | ---------------- method in this implementation
...
178 |     pub async fn schedule(
    |                  ^^^^^^^^

warning: `triton-llm` (lib) generated 4 warnings
warning: `triton-llm` (lib test) generated 4 warnings (4 duplicates)
    Finished `test` profile [unoptimized + debuginfo] target(s) in 17.05s
     Running unittests src/lib.rs (target/debug/deps/triton_llm_capi-1af7f785a632c7b4)