ignore failed to update plugins because of server disconnect

Summary:
To silence oocasional un actionable tasks
With such [logview](https://www.internalfb.com/logview/flipper_javascript/4e49a576ccc0f767c96cfbdbdc7d1123?trace_key=41bdca6a219d4800f091a662b5ce1405&trace_tab=shared&ds=%7B%22start%22%3A%22-1%20day%22%2C%22end%22%3A%22now%22%7D)

Reviewed By: mweststrate

Differential Revision: D62638786

fbshipit-source-id: ee8c1ff5a390061a9def4b7dfe7faf4ba0185760

desktop/flipper-ui/src/dispatcher/pluginManager.tsx

@@ -66,13 +66,15 @@ export default (
   },
 ) => {
   // This needn't happen immediately and is (light) I/O work.
-  if (window.requestIdleCallback) {
-    window.requestIdleCallback(() => {
-      refreshInstalledPlugins(store).catch((err) =>
-        console.error('Failed to refresh installed plugins:', err),
-      );
+  window.requestIdleCallback?.(() => {
+    refreshInstalledPlugins(store).catch((err: Error) => {
+      if (err.toString().includes('Not connected to Flipper server')) {
+        console.warn('Failed to refresh installed plugins:', err);
+      } else {
+        console.error('Failed to refresh installed plugins:', err);
+      }
     });
-  }
+  });
 
   let running = false;
   const unsubscribeHandlePluginCommands = sideEffect(