[CATALYST-1805] Remove PPR References in Catalyst Docs (#1274)

<!-- Ticket number or summary of work -->
# [CATALYST-1805] 

## What changed?
Remove references to PPR in the Catalyst docs since PPR was removed in
version 1.3.5

ping {names}

[CATALYST-1805]:
https://bigcommercecloud.atlassian.net/browse/CATALYST-1805?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQ

Author: jamesqquick

docs/storefront/catalyst/getting-started/deploying/overview.mdx

@@ -6,7 +6,6 @@ Catalyst depends on the following Next.js features which must be supported by yo
 
 * [Incremental Static Regeneration (ISR)](https://nextjs.org/docs/app/building-your-application/data-fetching/incremental-static-regeneration)
 * [Data Cache](https://nextjs.org/docs/app/building-your-application/caching#data-cache)
-* [Partial Prerendering (PPR)](https://nextjs.org/docs/app/building-your-application/rendering/partial-prerendering)
 * [Middleware](https://nextjs.org/docs/app/building-your-application/routing/middleware)
 
 ## Environment Variables

docs/storefront/catalyst/getting-started/guides/mailchimp-newsletter.mdx

@@ -51,7 +51,6 @@ export default async function DefaultLayout({ params, children }: Props) {
   );
 }
 
-export const experimental_ppr = true;
 ```
 
 Notice we used the `lazyOnload` strategy! This will prevent the script from loading until the browser has processed all the critical interactive elements and scripts.

docs/storefront/catalyst/overview.mdx

@@ -32,7 +32,7 @@ Out-of-the-box, Catalyst has the following capabilities you can use to further b
 
 * **Scalable GraphQL implementation**. Catalyst features scalable implementation of the GraphQL Storefront API.
 * **Minimal infrastructure dependencies**. Catalyst can be deployed to any hosting provider that supports Node.js.
-* **Making the most of modern Next.js features**. Catalyst uses [React server components](https://nextjs.org/docs/app/building-your-application/rendering/server-components) and [Suspense](https://react.dev/reference/react/Suspense) boundaries in preparation for [partial pre-rendering](https://nextjs.org/learn/dashboard-app/partial-prerendering).
+* **Making the most of modern Next.js features**. Catalyst uses [React server components](https://nextjs.org/docs/app/building-your-application/rendering/server-components) and [Suspense](https://react.dev/reference/react/Suspense).
 * **Components**. Catalyst provides _functionally_ complete ecommerce components and a pre-optimized site architecture for performance, SEO, and accessibility.
 * **Unopinionated visual design**. Visually, Catalyst is a "blank sheet of paper" that's ready to be transformed into a stellar ecommerce brand. Catalyst components use [Tailwind CSS](https://tailwindcss.com/) to accelerate development.