don't run commit test for repos specified with git

Until we find a safe way to run the commit format test for
repositories specified with git, we should skip that test
for those repos.
Added a conditional for the corresponding buildkite step
that will run the commit test only if BUILDKITE_REPO
doesn't start with `git@`.

Signed-off-by: Laura Loghin <lauralg@amazon.com>

.buildkite/pipeline.yml

@@ -194,6 +194,7 @@ steps:
   - label: "commit-format"
     commands:
       - pytest rust-vmm-ci/integration_tests/test_commit_format.py
+    if: build.env("BUILDKITE_REPO") !~ /^git@/
     retry:
       automatic: false
     agents: