chore: give pr pipeline release read permissions (#304929)

The core-ci task requires reading some companion extension releases. This PR modifies the permissions to allow the build to read those releases.

.github/workflows/pr.yml

@@ -10,7 +10,8 @@ concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true
 
-permissions: {}
+permissions:
+  contents: read
 
 env:
   VSCODE_QUALITY: 'oss'