Comparisons pagination fixes

[macobo]

Changes

Depends on https://github.com/plausible/analytics/pull/4692

Currently, when doing comparisons when breaking down by e.g. visit:browser dimension, zeroes would be incorrectly applied when small limits are in place. This is because the top 10 browsers today might not be the same as in previous period.

This PR fixes that by OR-ing together all dimension values from main result in comparison filter. Additionally, this filter is ignored when calculating totals as is needed for percentage/conversion rate calculations.

Rather than test every old endpoint separately, this PR adds a test-only endpoint for testing query logic as well.