Accept forceRefetch in plugin list requests (#34573)

## What changed

- Add the optional `forceRefetch` boolean to `PluginListParams` and generated schemas.
- Accept both omitted and enabled values without changing `plugin/list` behavior yet.
- Cover deserialization of the enabled value in the protocol tests.

GitOrigin-RevId: fd4145161e9779638bc0bf18118d5ab5b8478745

codex-rs/app-server-protocol/src/protocol/common.rs

@@ -1938,6 +1938,7 @@ mod tests {
             params: v2::PluginListParams {
                 cwds: None,
                 marketplace_kinds: None,
+                force_refetch: false,
             },
         };
         assert_eq!(plugin_list.serialization_scope(), None);