chore(docs): remove recommendation about using priority over loading=eager with next/image (#71562)

This recommendation to use `priority` instead of `loading=eager` is a
little confusing.

We don't want `priority` to be overused because it can hurt performance
so we can remove this recommendation from the documentation.

TLDR:

- use `priority` for LCP like a hero image above the fold
- use `loading=eager` for other images above the folder
- use `loading=lazy` (default) for everything below the fold
- use `fetchPriority=high` if you want to load an image out of order
that its found in the document

Author: styfle

docs/02-app/02-api-reference/01-components/image.mdx

@@ -373,8 +373,6 @@ A callback function that is invoked if the image fails to load.
 
 ### `loading`
 
-> **Recommendation**: This property is only meant for advanced use cases. Switching an image to load with `eager` will normally **hurt performance**. We recommend using the [`priority`](#priority) property instead, which will eagerly preload the image.
-
 ```js
 loading = 'lazy' // {lazy} | {eager}
 ```

docs/03-pages/02-api-reference/01-components/image-legacy.mdx

@@ -221,12 +221,6 @@ The `onLoadingComplete` function accepts one parameter, an object with the follo
 
 ### loading
 
-> **Attention**: This property is only meant for advanced usage. Switching an
-> image to load with `eager` will normally **hurt performance**.
->
-> We recommend using the [`priority`](#priority) property instead, which
-> properly loads the image eagerly for nearly all use cases.
-
 The loading behavior of the image. Defaults to `lazy`.
 
 When `lazy`, defer loading the image until it reaches a calculated distance from