chore: remove obsolete file

src/store/store-flag.d.ts

-// THIS FEATURE-FLAG FILE IS AUTOGENERATED,
-//  REMOVAL OR CHANGES WILL CAUSE RELATED TYPES TO STOP WORKING
-import "quasar/dist/types/feature-flag";
-
-declare module "quasar/dist/types/feature-flag" {
-  interface QuasarFeatureFlags {
-    store: true;
-  }
-}