perf(components): remove inefficient createSelector in Export

```
The result function returned its own inputs without modification.
This could lead to inefficient memoization and unnecessary re-renders.
Ensure transformation logic is in the result function, and extraction logic is in the input selectors.
```

https://redux.js.org/usage/deriving-data-selectors#createselector-overview

src/components/BoardControls/Export.tsx

@@ -6,20 +6,14 @@ import { createSelector } from '@reduxjs/toolkit';
 
 import { logEvent } from '../../firebase';
 import { useSelector } from '../../hooks';
-import type { RootState } from '../../types';
 import { transformToMarkdown } from './utils';
 
-const selectColumns = createSelector(
-  (state: RootState) => state.columns,
-  (columns) => columns,
-);
-
 interface Props {
   sx?: SxProps;
 }
 
 export default function Export(props: Props) {
-  const columns = useSelector(selectColumns);
+  const columns = useSelector((state) => state.columns);
   const items = useSelector((state) => state.items);
 
   async function copyBoardMarkdownToClipboard() {