Limit the impact of the connection notifications

Summary:
These notifications can get a bit annoying and in the way.

They are now keyyed on app so multiple notifications from the same app do not pile up

They are now allowed to cover the nav bar. Better to cover this than cover the plugin content area

Added a limit also

Reviewed By: mweststrate

Differential Revision: D55250950

fbshipit-source-id: c04d2efc88fad4d4c9b7f8278d85c2e7facedb35

desktop/flipper-ui/src/app-connection-updates.tsx

@@ -93,7 +93,7 @@ export const connectionUpdate = (
       content += `\n ${update.detail}`;
     }
     message.open({
-      key: update.key,
+      key: update.app,
       type: update.type === 'success-info' ? 'info' : update.type,
       content,
       className,

desktop/flipper-ui/src/sandy-chrome/SandyApp.tsx

@@ -48,7 +48,8 @@ export function SandyApp() {
   // Messages need to be pushed down to make sure they appear below
   // the navigation bar which has a height of 68px.
   message.config({
-    top: 68,
+    top: 10,
+    maxCount: 2,
   });
 
   useEffect(() => {