refactor(docker): simplify root user check
The code changes remove the unnecessary check for the presence of a Docker environment in multiple scripts. Instead, they now only check if the current user is not root. This simplifies the logic and improves readability.
- Simplify root user check in `check.sh`, `check_deps.sh`, `check_permissions.sh`, `check_root.sh`, `command_install.sh`, `core_exit.sh`, and `linuxgsm.sh`
- Remove redundant checks for Docker environment
- Improve code readability