### 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
if (Strings.hasLength(gcsClientSettings.getProjectId())) {
            storageOptionsBuilder.setProjectId(gcsClientSettings.getProjectId());
        } else {
            String defaultProjectId = null;
            try {
                defaultProjectId = SocketAccess.doPrivilegedIOException(ServiceOptions::getDefaultProjectId);
                if (defaultProjectId != null) {
                    storageOptionsBuilder.setProjectId(defaultProjectId);
                }
            } catch (Exception e) {
                logger.warn("failed to load default project id", e);
            }
            if (defaultProjectId == null) {
                try {
                    
                    
                    SocketAccess.doPrivilegedVoidIOException(() -> {
                        final String projectId = getDefaultProjectId();
                        if (projectId != null) {
                            storageOptionsBuilder.setProjectId(projectId);
                        }
                    });
                } catch (Exception e) {
                    logger.warn("failed to load default project id fallback", e);
                }
            }
        }
        if (gcsClientSettings.getCredential() == null) {
            try {
                storageOptionsBuilder.setCredentials(SocketAccess.doPrivilegedIOException(GoogleCredentials::getApplicationDefault));