Adding per_column_encryption_test

[argmarco-tkd]

Adding per_column_encryption_test

This test was migrated from an earlier version in dev_phase2. The intent is for it to exercise roundtrip encryption/decryption with per-column key definitions.

Testing

• Existing and new tests pass.

[github-actions]

Thanks for opening a pull request!

If this is not a minor PR. Could you open an issue for this pull request on GitHub? https://github.com/apache/arrow/issues/new/choose

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Then could you also rename the pull request title in the following format?

GH-${GITHUB_ISSUE_ID}: [${COMPONENT}] ${SUMMARY}

or

MINOR: [${COMPONENT}] ${SUMMARY}

See also:

• Other pull requests
• Contribution Guidelines - Contributing Overview

[avalerio-tkd]

LGTM, but it may be worth for @sofia-tekdatum to have a look too, just to confirm. Thanks for the test!