chore: improve missing pipe page (#962)

## TL;DR
Update missing Pipe page to be similar to missing Tile page

## How to test?
- [ ] Navigate to a non-existent Pipe, verify that missing Pipe page is
shown and clicking on link redirects to Pipes page

## Screenshots
### Before
<img width="1512" alt="Screenshot 2025-04-28 at 11 17 33 PM"
src="https://github.com/user-attachments/assets/ec2400d5-62a8-4785-a86f-11b701b97c2a"
/>


### After


https://github.com/user-attachments/assets/c1387d13-1e52-4f62-9a77-8baec29bd78b

Author: kevinkim-ogp

packages/frontend/src/pages/Editor/components/InvalidEditorPage.tsx

@@ -1,10 +1,46 @@
-import { Infobox } from '@opengovsg/design-system-react'
+import { Box, Stack, Text, VStack } from '@chakra-ui/react'
+import { Link } from '@opengovsg/design-system-react'
+
+import { PipeIcon } from '@/components/Icons/PipeIcon'
+import * as URLS from '@/config/urls'
+import styles from '@/pages/UnauthorizedTile/UnauthorizedTile.module.css'
 
 export default function InvalidEditorPage() {
-  // TODO (mal): check if this needs to be beautified
   return (
-    <Infobox variant="error">
-      Pipe not found, you may have transferred it to someone else 🤔
-    </Infobox>
+    <Stack
+      direction={{ base: 'column', md: 'row' }}
+      maxW="1000px"
+      margin="auto"
+      gap={8}
+      px={8}
+      alignItems="center"
+      justifyContent="center"
+    >
+      <Box
+        className={styles.flicker}
+        as={PipeIcon}
+        color="primary.300"
+        w="400px"
+        h="200px"
+        maxW="50vw"
+      />
+      <VStack alignItems={{ base: 'center', md: 'start' }} gap={2}>
+        <Text
+          textStyle="h4"
+          textAlign={{ base: 'center', md: 'left' }}
+          fontWeight="normal"
+        >
+          Pipe not found, you may have transferred it to someone else 🤔
+        </Text>
+        <Link
+          textStyle="h6"
+          textAlign={{ base: 'center', md: 'left' }}
+          fontWeight="normal"
+          href={URLS.FLOWS}
+        >
+          Back to your Pipes
+        </Link>
+      </VStack>
+    </Stack>
   )
 }