[patch] Update Dockerfile to restore USER

[ctyano]

Description

_description_with_details_andreasoning

Type of change

• [x] Bug fix
• [ ] New feature
• [ ] Refactoring (no functional changes, no api changes)
• [ ] Non-code changes (update documentation, pipeline, etc.)

Flags

• [ ] breaks backward compatibility
• [ ] requires a documentation update
• [ ] has untestable code

Related issue/PR

Delete if not applicable

• Fixes #issue
• Closes #PR

---

Checklist

• [ ] Followed the guidelines in the CONTRIBUTING document
• [ ] Added prefix [major]/[minor]/[patch]/[skip] in the PR title
• [ ] Tested and linted the code
• [ ] Commented the code
• [ ] Made corresponding changes to the documentation
• [ ] Confirmed no dropping in test coverage (by Codecov)
• [ ] Passed all pipeline checking
• [ ] Approved by >1 reviewer

Checklist for maintainer

• [ ] Use Squash and merge
• [ ] Double-confirm the merge message has prefix [major]/[minor]/[patch]/[skip]
• [ ] Delete the branch after merge

[kiyopiko]

LGTM