.json file export drops millisecond part of timestamp if fraction of second has all millisecond digits as 0 (full second)

[Archaeopteryx]

Issue Summary

.json file export drops millisecond part of timestamp if fraction of second has all millisecond digits as 0 (full second)

Steps to Reproduce

1. Open https://sql.telemetry.mozilla.org/queries/78112/source and run with a date range which includes 2021-02-02 (e.g. from "2021-02-02" to "2021-02-03").
2. From the vertical three dot menu at the top right, call "Show API key".
3. Copy the url for the JSON formatted file.
4. Open a new browser tab
5. Paste the url.
6. Load the file.
7. Save it.
8. Open it.
9. Search for: "classification_timestamp": "2021-02-04T05:25:56",
10. Compare with other "classification_timestamp" values.

Actual result: This one timestamp lacks the millisecond digits while others have them.
Expected result: Timestamps always contain millisecond digits (or are exported with microseconds)

Technical details:

A query in https://sql.telemetry.mozilla.org/ with the query below shows all microsecond digits are zero: 000000

select DATE_FORMAT(job_note.created, "%f")
from repository
join push
on repository.id = push.repository_id
join job
on push.id = job.push_id
join job_type
on job.job_type_id = job_type.id
join job_note
on job.id = job_note.job_id
where repository.name = "autoland" and
      push.revision = "dfaf3d7b742f2853b3677bd817b70328348ff851" and
      job_type.name = "test-windows7-32/opt-mochitest-plain-e10s-2"

• Redash Version: Version: 9.0.0-beta (3e76946)