Refactor Stella plugin

Summary:
1. Replace old FileSelector with the new FileSelector
2. Remove showOpenDialog from FlipperLib

Reviewed By: mweststrate

Differential Revision: D32667103

fbshipit-source-id: be8da034c2695f83b397b6c7d35bc6aee78d66e5

desktop/app/src/electron/initializeElectron.tsx

@@ -144,6 +144,7 @@ export function initializeElectron() {
           return {
             data,
             name: fileName,
+            path: filePath,
           };
         }),
       );