Fix Typo in Optimizing - Open Telemetry docs (#51729)

### What this PR does

This PR fixes a minor typo on the Vercel Open Telemetry Docs.
`It's not extensible and you should configure OpenTelemetry manually
(if) you need to customize your setup.`

That is all :)

Co-authored-by: JJ Kasper <jj@jjsweb.site>

docs/02-app/01-building-your-application/05-optimizing/08-open-telemetry.mdx

@@ -25,7 +25,7 @@ When you enable OpenTelemetry we will automatically wrap all your code like `get
 
 OpenTelemetry is extensible but setting it up properly can be quite verbose.
 That's why we prepared a package `@vercel/otel` that helps you get started quickly.
-It's not extensible and you should configure OpenTelemetry manually you need to customize your setup.
+It's not extensible and you should configure OpenTelemetry manually if you need to customize your setup.
 
 ### Using `@vercel/otel`