Fix perf-changelog PR link to #1478

Author: yhyang201

perf-changelog.yaml

@@ -2658,4 +2658,4 @@
     - dpskv4-gb300-sglang
   description:
     - "Update SGLang image to v0.5.12 and remove obsolete env vars for MTP configs"
-  pr-link: https://github.com/SemiAnalysisAI/InferenceX/pull/1477
+  pr-link: https://github.com/SemiAnalysisAI/InferenceX/pull/1478