Not able switch to certbot certificates if self-signed was used before

Steps to reproduce:
 
1. `docker compose up` with `SSL_CERTIFICATE_GENERATION: "self-signed"`
2. `docker compose up` with `SSL_CERTIFICATE_GENERATION: "certbot"`

`docker compose logs zulip`:

```
docker-zulip-zulip-1  | === End Bootstrap Phase ===
docker-zulip-zulip-1  | Certbot is not scheduled to run.
docker-zulip-zulip-1  | === Begin Run Phase ===
```
where I expected Certbot to run.