Fix DOCA OFED build

Disable Pulp auth proxy (deployed too late for DOCA DNF repository).

(cherry picked from commit 1b17a95)

Author: priteau

etc/kayobe/environments/ci-doca-builder/stackhpc-ci.yml

@@ -7,3 +7,6 @@ stackhpc_repos_enabled: true
 enable_docker_repo: false
 dnf_install_doca: true
 dnf_enable_doca_modules: false
+
+# Disable Pulp auth proxy (deployed too late for DOCA DNF repository setup).
+stackhpc_repo_mirror_auth_proxy_enabled: false