warmer validate and copy registry mirror to registry map

[prima101112]

Fixes #3134

Description

seems like warmer is not updated when 1.21 is updated registry mirror mapped to registry map and warmer are also using remote package here

https://github.com/GoogleContainerTools/kaniko/commit/1bf529e6d9d275f57581bb51fa3b476cdc636eda

warmer is not touch and some users actually use warmer and using --registry-mirror flag

Submitter Checklist

These are the criteria that every PR should meet, please check them off as you review them:

• [ ] Includes unit tests
• [ ] Adds integration tests if needed.

Reviewer Notes

• [ ] The code flow looks good.
• [ ] Unit tests and or integration tests added.

Release Notes

warmer will have same behaviour when using --registry-mirror also add --registry-map to warmer