Comittizen runs twice when using the `prepare-commit-msg` hook

Steps to re-produce

1. Create a `prepare-commit-msg` hook:
``` #sh
#!/bin/sh
. "$(dirname "$0")/_/husky.sh"

exec < /dev/tty && node_modules/.bin/cz --hook || true

```
2. Run `git commit`
3. Follow the CLI
4. Everything works as expected.
5. Run `git cz`
6. Follow the CLI
7. Everything goes as expected except that, after we complete the wizard, Comittizen opens up again.

Is there any way to prevent `prepare-commit-msg` hook from running when executing `git cz`?

使用提供的 prepare-commit-msg hook 重现问题，然后跟踪 git cz 如何调用 CLI，以及该 hook 是如何触发的。当运行 git cz 时只打开一次 Commitizen 向导，同时该 hook 仍能对 git commit 正常工作时，修复才算完成。

由索引模型根据 Issue 内容生成。