Show quick notification if plugin interaction fails

Summary:
Per title, if a plugin makes a client call, show a quick notif so that the user knows why his plugin interactions aren't responding in case the plugin doesn't use `isConnected` guards.

This might turn out to be too spammy, but I think it should be ok.

Reviewed By: nikoant

Differential Revision: D26277099

fbshipit-source-id: bd555ea84acae6189ec7f8fff0fc0a088dbc5337

desktop/app/src/Client.tsx

@@ -40,6 +40,7 @@ import {flipperMessagesClientPlugin} from './utils/self-inspection/plugins/Flipp
 import {getFlipperLibImplementation} from './utils/flipperLibImplementation';
 import {freeze} from 'immer';
 import GK from './fb-stubs/GK';
+import {message} from 'antd';
 
 type Plugins = Array<string>;
 
@@ -601,8 +602,14 @@ export default class Client extends EventEmitter {
 
       const mark = this.getPerformanceMark(metadata);
       performance.mark(mark);
-      if (!this.connected) {
+      if (!this.connected.get()) {
+        message.warn({
+          content: 'Not connected',
+          key: 'appnotconnectedwarning',
+          duration: 0.5,
+        });
         reject(new Error('Not connected to client'));
+        return;
       }
       if (!fromPlugin || this.isAcceptingMessagesFromPlugin(plugin)) {
         this.connection!.requestResponse({
@@ -714,7 +721,7 @@ export default class Client extends EventEmitter {
   deinitPlugin(pluginId: string) {
     this.activePlugins.delete(pluginId);
     this.sandyPluginStates.get(pluginId)?.disconnect();
-    if (this.connected) {
+    if (this.connected.get()) {
       this.rawSend('deinit', {plugin: pluginId});
     }
   }

desktop/themes/typography.less

@@ -82,7 +82,7 @@
 .ant-notification-notice-message {
   color: @background-default;
 }
-.ant-notification-notice {
+.ant-notification-notice, .ant-message-notice-content {
   background: @text-color-primary;
   color: @background-default;
 }