Remove docker pull prefix from registry clipboard feature

What does this MR do?

Remove the docker pull prefix on container registry clipboard feature

Are there points in the code the reviewer needs to double check?

No

Why was this MR needed?

As stated here:

#46314 (closed) :

Remove docker pull from registry clipboard text. Nowadays the local testing with docker pull <registry_image> is more or less outdated. Often you use docker-compose.yml's, equivalent kubernetes yml or Dockerfiles where you just need the image tag. So let's remove docker pull

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
• Conform by the merge request performance guides
• Conform by the style guides

What are the relevant issue numbers?

#46314 (closed) #45968 (closed)