docs: simplify private ECR note

Author: Hkhan161

cerebrium/container-images/defining-container-images.mdx

@@ -262,7 +262,7 @@ Public ECR images from the `public.ecr.aws` registry work without authentication
 docker_base_image_url = "public.ecr.aws/lambda/python:3.11"
 ```
 
-However, **private ECR images** (e.g., `123456789.dkr.ecr.us-east-1.amazonaws.com/my-image`) require authentication. See [Using Private Docker Registries](/cerebrium/container-images/private-docker-registry) for setup instructions.
+However, **private ECR images** require authentication. See [Using Private Docker Registries](/cerebrium/container-images/private-docker-registry) for setup instructions.
 
 ## Custom Runtimes