Fix Redux Middleware types (#29800)

app/javascript/mastodon/store/middlewares/errors.ts

@@ -30,7 +30,8 @@ function isActionWithmaybeAlertParams(
   return isAction(action);
 }
 
-export const errorsMiddleware: Middleware<Record<string, never>, RootState> =
+// eslint-disable-next-line @typescript-eslint/ban-types -- we need to use `{}` here to ensure the dispatch types can be merged
+export const errorsMiddleware: Middleware<{}, RootState> =
   ({ dispatch }) =>
   (next) =>
   (action) => {

app/javascript/mastodon/store/middlewares/sounds.ts

@@ -51,7 +51,8 @@ const play = (audio: HTMLAudioElement) => {
 };
 
 export const soundsMiddleware = (): Middleware<
-  Record<string, never>,
+  // eslint-disable-next-line @typescript-eslint/ban-types -- we need to use `{}` here to ensure the dispatch types can be merged
+  {},
   RootState
 > => {
   const soundCache: Record<string, HTMLAudioElement> = {};