CI Fix incorrect lockfile in xbuildenv (pyodide#5749)

The xbuildenv should contain the lockfile from the prebuilt packages set,
not one that built from this repository. This fixes it.

Author: ryanking13

.circleci/config.yml

@@ -767,7 +767,7 @@ workflows:
 
       - create-xbuild-env:
           requires:
-            - build-core-packages
+            - build-full-packages
           filters:
             tags:
               only: /.*/