[Bugfix] sort migrated map array to get deterministic result

[yun-yeo]

Summary of changes

close #535

Report of required housekeeping

• Github issue OR spec proposal link
• Wrote tests
• Updated API documentation (client/lcd/swagger-ui/swagger.yaml)
• Added a relevant changelog entry: clog add [section] [stanza] [message]

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(FOR ADMIN) Before merging

• Added appropriate labels to PR
• Squashed all commits, uses message "Merge pull request #XYZ: [title]" (coding standards)
• Confirm added tests are consistent with the intended behavior of changes
• Ensure all tests pass

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (main@d6037b9). Click here to learn what that means.
The diff coverage is n/a.

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