fix(codeserver): use beefy amd64 builder in Tekton on-pull-request pipeline configuration

Author: jiridanek

.tekton/odh-workbench-codeserver-datascience-cpu-py312-pull-request.yaml

@@ -43,7 +43,7 @@ spec:
     value: true
   - name: build-platforms
     value:
-    - linux/x86_64
+    - linux-extra-fast/amd64
     - linux-m2xlarge/arm64
     - linux/ppc64le
     - linux/s390x