Tech report data tooltips show datetime in local timezone

[rviscomi]

When you hover over a data point in the tech report charts, the datetime is shown in the local timezone. For me in GMT-5, this leads to crawl dates on the first of the month being displayed as the last day of the previous month.

Since the time of the crawl isn't relevant, we should only show the date. And to avoid discrepancies caused by local timezones, the date should be formatted in UTC.

In the example above, I'd expect the date to appear as something like "Feb 1 2024".