Unable to use `pgcli service={service}`

## Description

I am running a PostgreSQL server in a Docker container and using Secure TCP/IP Connections with SSL.

In my `postgresql.conf` file, I include the following lines:

```
ssl = on
ssl_ca_file = '/run/secrets/ca.crt'
ssl_cert_file = '/run/secrets/server.crt'
ssl_key_file = '/run/secrets/server.key'
# This setting is on by default but it’s always a good idea to
# be explicit when it comes to security.
ssl_prefer_server_ciphers = on
# TLS 1.3 will give the strongest security and is advised when
# controlling both server and clients.
ssl_min_protocol_version = 'TLSv1.3'
```

I have a `.pg_service.conf` file where I define a service named `{service}`:

```
[{service}]
host={host}
port={port}
user={user}
dbname={dbname}
sslmode=verify-full
sslrootcert=/path/to/ca.crt
sslcert=/path/to/user.crt
sslkey=/path/to/user.key
```

The command `psql service={service}` prompts for the password of the user included in the service definition and successfully connects to the specified database afterwards.

However, the command `pgcli service={service}` returns the following error message:

```
connection failed: FATAL: connection requires a valid client certificate
connection to server at "{host}", port {port} failed: FATAL: no pg_hba.conf entry for host "{host}", user "{user}", database "{dbname}", no encryption
```

In the PostgreSQL server logs I see the following entries:

```
postgres | 2024-08-06 10:50:35.387 GMT [117]: [1-1] user={user},db={dbname} FATAL: connection requires a valid client certificate
postgres | 2024-08-06 10:50:35.390 GMT [118]: [1-1] user={user},db={dbname} FATAL: no pg_hba.conf entry for host "{host}", user "{user}", database "{dbname}", no encryption
```

Note that the `pg_hba.conf` I am using contains the following line:

```
hostssl {dbname} {user} {host}/32 scram-sha-256 clientcert=verify-full
```

Surprisingly, the command `pgcli "postgresql://{user}@{host}/{dbname}?port={port}&sslmode=verify-full&sslkey=/path/to/user.key&sslcert=/path/to/user.crt&sslrootcert=/path/to/ca.crt"` successfully connects to the specified database after prompting for the user password. Same thing happens if I replace `pgcli` with `psql`.

Note that in the `.pg_service.conf` file I am using the very same paths to the `user.key`, `user.crt`, and `ca.crt` files.

## Your environment

- Debian 12 (bookworm)
- pgcli 4.1.0 - python 3.12.4 (installed with conda/mamba).
- Packages included in my conda/mamba env include, among other packages:
- ca-certificates 2024.7.4-hbcca054_0
- certifi 2024.7.4-pyhd8ed1ab_0
- openssl 3.3.1-h4bc722e_2
- postgresql 16.3-h8e811e2_0

Start by comparing pgcli service={service} handling with the working PostgreSQL URI command, using the .pg_service.conf entries and the PostgreSQL connection settings in postgresql.conf and pg_hba.conf. Reproduce the failure with the listed commands and verify that service-based connections use the same client certificate, key, CA, and SSL settings as the URI form.

Written by the indexing model from the issue text.