restore cargo vendor in test suite (#4886)

## Issue Addressed

resolves #4440

## Proposed Changes

restore our `cargo vendor` test in CI

changes to `c-kzg` here mean we no longer have to compile it twice and get duplicate source errors: #4862

Co-authored-by: realbigsean <[email protected]>

Author: realbigsean

.github/workflows/test-suite.yml

@@ -364,10 +364,8 @@ jobs:
       run:  make arbitrary-fuzz
     - name: Run cargo audit
       run: make audit-CI
-# TODO(sean): re-enable this when we can figure it out with c-kzg
-# Issue: https://github.com/sigp/lighthouse/issues/4440
-#    - name: Run cargo vendor to make sure dependencies can be vendored for packaging, reproducibility and archival purpose
-#      run:  CARGO_HOME=$(readlink -f $HOME) make vendor
+    - name: Run cargo vendor to make sure dependencies can be vendored for packaging, reproducibility and archival purpose
+      run:  CARGO_HOME=$(readlink -f $HOME) make vendor
   check-msrv:
     name: check-msrv
     runs-on: ubuntu-latest