Remove unused push expansion flags (`push_path`, `push_bucket`, `push_bucket_new`, `push_role_arn`, `push_name`, `push_arch`, `mciuploads_binary_permissions_push`, `mciuploads_binary_visibility_push`) from the `enterprise-rhel-8-64-bit` template in `test_dev_master_branch_only.yml`.

These flags are only consumed by the `push` and `crypt_push` tasks, both tagged `incompatible_development_variant` and never run on this dev variant. The `hot_backups-rhel-8-64-bit` variant that inherits the expansions template also runs no push tasks. The release variant in `test_release.yml` defines its own independent copy of these flags and is unaffected.

These flags disable remote caching since they're intended for release variants only.