Empty doadmin password for new postgres cluster

Hi,

I've recently noticed that I can no longer get `doadmin` user password when creating a new database server.

```go
client := godo.NewClient(oauth2.NewClient(ctx, tokenSource))

client.Databases.Create(ctx, &godo.DatabaseCreateRequest{
Name: "testname",
EngineSlug: "pg",
Version: "16",
SizeSlug: "db-s-1vcpu-1gb",
Region: "nyc1",
NumNodes: 1,
})
```

When the database server status is `online` I check `database.Connection.Password` and it's always empty. At the same time I can get the password from UI and using `doctl`.

My go version: `go version go1.23.0 darwin/arm64`
Tried with the latest sdk `github.com/digitalocean/godo v1.128.0` but also didn't work with the old one. It used to work before.

Start with the Databases.Create call shown in the report and inspect database.Connection.Password once the cluster is online, comparing it with the UI and doctl results. Done means identifying whether the empty value comes from SDK response handling or the service response and documenting a reproducible fix or limitation.

Written by the indexing model from the issue text.