fix sveltekit redis env loading (#1076)

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### Type of Change

- [ ] New Example
- [ ] Example updates (Bug fixes, new features, etc.)
- [ ] Other (changes to the codebase, but not to examples)

### New Example Checklist

- [ ] 🛫 `npm run new-example` was used to create the example
- [ ] 📚 The template wasn't used but I carefuly read the [Adding a new
example](https://github.com/vercel/examples#adding-a-new-example) steps
and implemented them in the example
- [ ] 📱 Is it responsive? Are mobile and tablets considered?

storage/kv-redis-sveltekit/src/routes/+page.server.ts

@@ -1,12 +1,22 @@
-import { REDIS_URL, KV_URL } from '$env/static/private'
+import * as rawEnv from '$env/static/private'
 import { createClient } from 'redis'
 
-const kv = await createClient({
-  url: REDIS_URL ?? KV_URL,
-}).connect()
+let client: Awaited<ReturnType<typeof createClient>> | null = null
+
+const getClient = async () => {
+  if (!client) {
+    client = await createClient({
+      url:
+        (rawEnv as { REDIS_URL?: string }).REDIS_URL ??
+        (rawEnv as { KV_URL?: string }).KV_URL,
+    }).connect()
+  }
+  return client
+}
 
 /** @type {import('./$types').PageLoad} */
 export async function load() {
+  const kv = await getClient()
   const pageVisits = await kv.get('pageVisits')
   await kv.set('pageVisits', Number.parseInt(pageVisits ?? '0', 10) + 1)
   const updatedPageVisits = await kv.get('pageVisits')