feat(copy_to_json): add date_format/timestamp_format/time_format for JSON format copy

[linyihai]

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Refer to a related PR or issue link (optional)

Closed #6287

What's changed and what's your intention?

Same as #6995 but for JSON Format.

PR Checklist

Please convert it to a draft if some of the following conditions are not met.

• I have written the necessary rustdoc comments.
• I have added the necessary unit tests and integration tests.
• This PR requires documentation updates.
• API changes are backward compatible.
• Schema or data changes are backward compatible.

[gemini-code-assist]

Summary of Changes

Hello @linyihai, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces new formatting options for JSON output, specifically for date, time, and timestamp fields. These changes enhance the flexibility of the COPY TO command when exporting data in JSON format, allowing users to specify their desired output formats. The implementation includes modifications to the JsonFormat struct and the stream_to_json function, along with updates to existing tests to validate the new functionality.

Highlights

• New Features: Adds date_format, timestamp_format, and time_format options for JSON format when copying data, mirroring the functionality already present for CSV format.
• Code Changes: Modifies JsonFormat struct to include optional fields for timestamp_format, time_format, and date_format. Updates stream_to_json function to utilize these formats when writing JSON data.
• Testing: Updates tests to include time formatting options, ensuring the new functionality works as expected.

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[gemini-code-assist]

Code Review

This pull request adds support for date_format, timestamp_format, and time_format options for JSON format exports, aligning it with the functionality already present for CSV. The implementation is sound, introducing the new format options to JsonFormat and using them to configure arrow::json::WriterBuilder. The accompanying test changes are good, but there's an opportunity to improve integration test coverage. I've provided a couple of suggestions to enhance code conciseness and test completeness.

[gemini-code-assist]

The new time_format option for JSON export is not covered in this integration test. Please consider adding a column with a TIME data type to the demo table and a test case that uses time_format to ensure the feature is fully tested.

[linyihai]

See #6995 (comment)