fix: Remove link to non existing example

Based on the wayback machine, this never existed
https://web.archive.org/web/20240101000000*/%20https://p5js.org/examples/3d-blur-using-framebuffer-depth.html

Author: ff6347

src/content/tutorials/en/layered-rendering-with-framebuffers.mdx

@@ -544,8 +544,7 @@ function draw() {
 
 If you want to customize how close to or far from the camera an object needs to be to get depth values of 0 or 1, specify near and far values in [`perspective()`](https://p5js.org/reference/#/p5/perspective).
 
-*Depth-based blur shaders are more advanced and are beyond the scope of this tutorial. If you are interested in how they work, you can look at* [*an example of Framebuffer depth blur*](https://p5js.org/examples/3d-blur-using-framebuffer-depth.html)*.*
-
+*Depth-based blur shaders are more advanced and are beyond the scope of this tutorial.*
 
 <Callout>
 Can you make a moody, rainy scene using a fog shader to add to the atmosphere?