fix off-by-one error

[dorner]

No description provided.

[cielf]

Hey @dorner -- When I run this, a couple of the tests in distributions_by_county_system_spec.rb fail, but when I run them in main they pass. Could you elaborate on what this change is about?

[coalest]

@cielf A PR of mine was just merged and it added these flaky tests. They test the new filtering by "Prior Year" or "Last 12 Months" options in the date range picker. They create distributions right before and right after the date range filter. But currently there is some overlap based on time so the tests are flaky.

[cielf]

So, my understanding is that this fails dependent on the time of day it is run, then.

[coalest]

That's what I thought at first, but the fact that one of the specs is still flaky with this PR (that sets an artificial date and time), makes me think there is something additional wrong. My theory is it's also time zone related between UTC vs the time zone set in the test environment (US west coast).

I think a combination of this PR plus the one I just created will fix the issue.

[dorner]

This was a failed attempt at fixing the flaky test. @coalest fixed it in a different PR.