fix: add mem frac for sglang dsr1 8gpu (CP #5260) (#5282)

Signed-off-by: hongkuanz <hongkuanz@nvidia.com>
Co-authored-by: Anant Sharma <anants@nvidia.com>

Author: tedzhouhk

recipes/deepseek-r1/sglang/disagg-8gpu/deploy.yaml

@@ -60,6 +60,8 @@ spec:
             - decode
             - --disaggregation-bootstrap-port
             - "30001"
+            - --mem-fraction-static
+            - "0.75"
             - --host
             - 0.0.0.0
             - --prefill-round-robin-balance
@@ -97,6 +99,8 @@ spec:
             - prefill
             - --disaggregation-bootstrap-port
             - "30001"
+            - --mem-fraction-static
+            - "0.75"
             - --host
             - 0.0.0.0
             - --load-balance-method