fix Dockerfile steps order

[NoamShaish]

Fixes #11137.

Description

This PR fix the Docker build sequence which is broken.
I moved the copy of the builder opt directory to be before the creation of /opt/druid/var since it collides with the copied content.

Key changed/added files in this PR

• /distribution/docker/Dockerfile

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This PR has:

• been self-reviewed.
• added documentation for new or modified features or behaviors.
• added Javadocs for most classes and all non-trivial methods. Linked related entities via Javadoc links.
• added or updated version, license, or notice information in licenses.yaml
• added comments explaining the "why" and the intent of the code wherever would not be obvious for an unfamiliar reader.
• added unit tests or modified existing tests to cover new code paths, ensuring the threshold for code coverage is met.
• added integration tests.
• been tested in a test Druid cluster.

[xvrl]

Hi @NoamShaish, your change seems to undo the docker image size optimization introduced in #10506 which introduced this bug. I believe #11167 should fix the problem while avoiding the increase in the image size.

[stale]

This pull request has been marked as stale due to 60 days of inactivity. It will be closed in 4 weeks if no further activity occurs. If you think that's incorrect or this pull request should instead be reviewed, please simply write any comment. Even if closed, you can still revive the PR at any time or discuss it on the dev@druid.apache.org list. Thank you for your contributions.

[FrankChen021]

Hello @NoamShaish Thank you for your contribution. There should be no such problem since 0.23