### Elasticsearch Version

8.x (any version where we have added support for proxies with a GCS repo)

### Installed Plugins

_No response_

### Java Version

_bundled_

### OS Version

N/A

### Problem Description

When configuring a GCS repository with HTTP proxy settings ([doc](https://www.elastic.co/guide/en/elasticsearch/reference/8.0/repository-gcs.html#repository-gcs-client)), we do not pass along the proxy settings to other `HttpTransportOptions` instances that we create. This can lead to timeout errors when the GCS Client tries to get a token, with the following error message:
```
Error getting access token for service account: Connect timed out, iss: ...
```

The workaround is to set the HTTP proxy settings on the JVM level rather than when defining the GCS repository, using `java.net.useSystemProxies` or `http.proxyHost`/`http.proxyPort`.

### Steps to Reproduce

[Setting up a GCS repository](https://www.elastic.co/guide/en/elasticsearch/reference/8.0/repository-gcs.html) with HTTP proxy settings (while every other non-proxied GCP call is blocked) could lead to this issue.

### Logs (if relevant)

_No response_
modules/repository-gcs/src/main/java/org/elasticsearch/repositories/gcs/GoogleCloudStorageService.java
try (InputStream input = connection.getInputStream()) {
            if (connection.getResponseCode() == 200) {
                try (BufferedReader reader = new BufferedReader(new InputStreamReader(input, UTF_8))) {
                    return reader.readLine();
                }
            }
        }
        return null;
    }
    /**
     * Converts timeout values from the settings to a timeout value for the Google
     * Cloud SDK
     **/
    static Integer toTimeout(final TimeValue timeout) {
        
        if (timeout == null || TimeValue.ZERO.equals(timeout)) {
            
            return -1;
        }
        
        if (TimeValue.MINUS_ONE.equals(timeout)) {
            
            return 0;
        }
        return Math.toIntExact(timeout.getMillis());
    }
    
    void notifyProxyIsSet(Proxy proxy) {}
}