remove unused imports

frontend/src/pages/HistoricalCalendarPrices.tsx

@@ -1,5 +1,4 @@
-import { signal, computed } from "@preact/signals";
+import { useEffect } from "preact/hooks";
-import { useEffect, useRef } from "preact/hooks";
 import { trpc } from "../trpc.js";
 import {
   Chart as ChartJS,
@@ -14,15 +13,9 @@ import {
   Container,
   Grid,
   Typography,
-  TextField,
-  Select,
-  MenuItem,
   Paper,
-  Button,
   Popper,
   ClickAwayListener,
-  Slider,
-  Box,
 } from "@mui/material";
 import {
   availableUnderlyings,