[Cherry-Pick][BugFix] Fix real token exceeding max_batched_tokens limit(#7438) (#7440)

* fix max_num_batched_tokens error compute

* add temperatory solution

* fix bug

Author: freeliuzc

fastdeploy/engine/sched/resource_manager_v1.py

@@ -718,7 +718,17 @@ def get_enough_request(request, scheduled_reqs):
             scheduled_reqs: list[Request] = []
             preempted_reqs: list[Request] = []
             error_reqs: list[tuple[str, str]] = []
-            token_budget = self.config.scheduler_config.max_num_batched_tokens
+            tokens_per_seq = (
+                (self.config.speculative_config.num_speculative_tokens + 1)
+                if self.config.speculative_config is not None
+                else 1
+            )
+            token_budget = (
+                self.config.scheduler_config.max_num_batched_tokens
+                - self.config.scheduler_config.max_num_seqs * tokens_per_seq
+            )
+            # temperatory solution to avoid negative token_budget
+            token_budget = max(token_budget, min(self.config.scheduler_config.max_num_batched_tokens, 512))
             need_abort_requests = []  # users trigger abortion
 
             # First, schedule the RUNNING requests.