[BUG] letsencrypt handshake not working on IPv6 only

### What happened?

I'm aware that the IPV6=yes feature is currently in beta and not ready for production - so this report is likely for the backlog.
I created a simple static website - and tried to enable letsencrypt to acquire a certificate - however, that is failing - bunkerweb startup procedure stops at this point:

```
root-bw-scheduler-1 | [2023-11-25 10:07:55] - API - ℹ️ - Successfully sent API request to http://root-bunkerweb-1:5000/reload
root-bw-scheduler-1 | [2023-11-25 10:07:55] - SCHEDULER - ℹ️ - Successfully reloaded nginx
root-bw-scheduler-1 | [2023-11-25 10:07:55] - SCHEDULER - ℹ️ - Executing job scheduler ...
root-bunkerweb-1 | bwapi 10.20.30.3 - - [25/Nov/2023:10:07:55 +0000] "POST /reload HTTP/1.1" 200 58 "-" "bwapi"
root-bunkerweb-1 | 2023/11/25 10:07:55 [emerg] 50#50: cannot load certificate "/var/cache/bunkerweb/letsencrypt/etc/live/www.example.com/fullchain.pem": BIO_new_file() failed (SSL: error:80000002:system library::No such file or directory:calling fopen(/var/cache/bunkerweb/letsencrypt/etc/live/www.example.com/fullchain.pem, r) error:10000080:BIO routines::no such file)
root-bunkerweb-1 | 2023/11/25 10:08:00 [notice] 50#50: signal 17 (SIGCHLD) received from 115
root-bunkerweb-1 | 2023/11/25 10:08:00 [notice] 50#50: unknown process 51 exited with code 0
```

### How to reproduce?

running bunkerweb v1.5.3 in docker on debian12 - made a simple static website under www.example.com
for this case the connection is only working on IPv6 and hence I only made an AAAA DNS record
the connectivity to bunkerweb on port 80 was tested from outside by curl and was ok
then I changed the two letsencrypt lines in the config file from "no" to "yes" and restarted docker compose

letsencrypt's standard behavior is to use IPv6 / AAAA records first (which causes its own issues sometimes) so I assume it is sufficiently tested under IPv6 already

I was able to get a certificate successfully, so no "file not found" error anymore when I added a IPv4 portforwarding and an A record for the domain - I assume that there is just a tiny issue in the certificate challenge handshake to verify the domain URL path which does not yet work under IPv6 only

### Configuration file(s) (yaml or .env)

```YAML
version: "3.5"

services:

bunkerweb:
image: bunkerity/bunkerweb:1.5.3
ports:
- 80:8080
- 443:8443
labels:
- "bunkerweb.INSTANCE=yes"
environment:
- DNS_RESOLVERS=8.8.8.8 8.8.4.4
- USE_IPV6=yes
- API_WHITELIST_IP=127.0.0.0/8 10.20.30.0/24
- MULTISITE=yes
- SERVER_NAME=www.example.com
- www.example.com_SERVER_NAME=www.example.com
- www.example.com_AUTO_LETS_ENCRYPT=yes
- www.example.com_EMAIL_LETS_ENCRYPT=privacy@example.com
- www.example.com_USE_LETS_ENCRYPT_STAGING=yes
volumes:
- www:/var/www/html
networks:
- bw-universe
- bw-services

bw-scheduler:
image: bunkerity/bunkerweb-scheduler:1.5.3
depends_on:
- bunkerweb
- bw-docker
volumes:
- bw-data:/data
environment:
- DOCKER_HOST=tcp://bw-docker:2375
networks:
- bw-universe
- bw-docker

bw-docker:
image: tecnativa/docker-socket-proxy:nightly
volumes:
- /var/run/docker.sock:/var/run/docker.sock:ro
environment:
- CONTAINERS=1
- LOG_LEVEL=warning
networks:
- bw-docker

volumes:
bw-data:
www:

networks:
bw-universe:
name: bw-universe
ipam:
driver: default
config:
- subnet: 10.20.30.0/24
bw-docker:
name: bw-docker
bw-services:
name: bw-services
enable_ipv6: true
ipam:
config:
- subnet: fd00:13:37::/48
gateway: fd00:13:37::1
```

### Relevant log output

```shell
root-bw-scheduler-1 | [2023-11-25 10:07:55] - API - ℹ️ - Successfully sent API request to http://root-bunkerweb-1:5000/reload
root-bw-scheduler-1 | [2023-11-25 10:07:55] - SCHEDULER - ℹ️ - Successfully reloaded nginx
root-bw-scheduler-1 | [2023-11-25 10:07:55] - SCHEDULER - ℹ️ - Executing job scheduler ...
root-bunkerweb-1 | bwapi 10.20.30.3 - - [25/Nov/2023:10:07:55 +0000] "POST /reload HTTP/1.1" 200 58 "-" "bwapi"
root-bunkerweb-1 | 2023/11/25 10:07:55 [emerg] 50#50: cannot load certificate "/var/cache/bunkerweb/letsencrypt/etc/live/www.example.com/fullchain.pem": BIO_new_file() failed (SSL: error:80000002:system library::No such file or directory:calling fopen(/var/cache/bunkerweb/letsencrypt/etc/live/www.example.com/fullchain.pem, r) error:10000080:BIO routines::no such file)
root-bunkerweb-1 | 2023/11/25 10:08:00 [notice] 50#50: signal 17 (SIGCHLD) received from 115
root-bunkerweb-1 | 2023/11/25 10:08:00 [notice] 50#50: unknown process 51 exited with code 0
```

### BunkerWeb version

1.5.3

### What integration are you using?

Docker

### Linux distribution (if applicable)

debian12

### Removed private data

- [X] I have removed all private data from the configuration file and the logs

### Code of Conduct

- [X] I agree to follow this project's Code of Conduct