fix: revert max-num-seqs to 1 — segfault during profile_run with n=2

Profile run with 2 sequences triggers segfault in torch.distributed.gather
during determine_num_available_blocks. t2_n_2 is worth 1 point, not worth
the crash risk. max_completion_tokens fix is the priority.

computility-run.yaml

@@ -15,7 +15,7 @@ command:
     - -tp
     - '4'
     - --max-num-seqs
-    - '2'
+    - '1'
     - --disable-log-requests
     - --disable-frontend-multiprocessing
     - --max-num-batched-tokens