containers/teuthology-dev: Remove access token

containers/teuthology-dev: Remove access token

This container is built and pushed via GitHub Actions. GHA likes to provision a
personal access token for each job that gives tightly-scoped access to the git
repository to the job. When we build our container, we end up including
`.git/config`, which contains the token. Later, in ceph-dev-stack's CI, an
`ls-remote` is run against ceph.git, which ends up causing git to prompt for
credentials even though the repo is public. Removing the token should allow
reading all the relevant repos from the built container image.

Signed-off-by: Zack Cerza <zack@redhat.com>