Remove Name/Namespace fields from upstream default (#11456)

The UpstreamConfig.Defaults field does not support setting Name or
Namespace because the purpose is to apply defaults to all upstreams.
I think this was just missed in the docs since those fields would
error if set under Defaults.

i.e. this is not supported:

```
UpstreamConfig {
  Defaults {
    Name = "foo"
    Namespace = "bar"
    # Defaults config here
  }
}
```

website/content/docs/connect/config-entries/service-defaults.mdx

@@ -230,6 +230,7 @@ spec:
   }
 }
 ```
+
 </CodeTabs>
 
 </Tab>
@@ -338,8 +339,7 @@ spec:
                 name: 'Protocol',
                 type: 'string: ""',
                 description:
-                  `The protocol for the upstream listener.
+                  `The protocol for the upstream listener.<br><br>
-                  
                   NOTE: The protocol of a service should ideally be configured via the
                     [\`protocol\`](/docs/connect/config-entries/service-defaults#protocol)
                     field of a
@@ -454,18 +454,8 @@ spec:
         {
           name: 'Defaults',
           type: 'UpstreamConfig: <optional>',
-          description: `Default configuration that applies to all upstreams of the given service.`,
+          description: `Default configuration that applies to all upstreams of this service.`,
           children: [
-            {
-              name: 'Name',
-              type: 'string: ""',
-              description: 'The upstream name to apply the configuration to.',
-            },
-            {
-              name: 'Namespace',
-              type: 'string: ""',
-              description: 'The namespace of the upstream.',
-            },
             {
               name: 'Protocol',
               type: 'string: ""',
@@ -697,7 +687,7 @@ spec:
           ],
         },
       ],
-    },
+    }
   ]}
 />