[sdk-platform-java] host is not updated when universe domain is specified

When a client specifies a universe domain, the `host` value does not get automatically updated to match. For example, if I create a storage client:

`Storage storage = StorageOptions.grpc().setUniverseDomain("my-universe-domain.com").build().getService();`

Then
`storage.getOptions().getUniverseDomain()` properly returns `my-universe-domain`, but `storage.getOptions.getHost()` just returns `www.googleapis.com`, when it should return `https://storage.my-universe-domain.com`