Returns the results of the A/B tests of the given form. Each report covers one A/B setup and contains
the period it ran for (startedAt, and completedAt once it finished), the winning version, and
per-version statistics.

Both running (enabled) and finished (completed) setups are returned, so a test that is still
collecting data is included with its statistics so far. If the form has no A/B setups, the endpoint
responds with 200 OK and an empty reports array rather than 404.

Versions and split: every report lists its versions in versionStatistics. splitValue is the
percentage of eligible traffic that is routed to that version; the split values of a setup add up to
100. Statistics per version use the same counters as the form report endpoints: views,
interactions, submits, and signups. Compare versions using rates derived from views rather than
raw counts, because an uneven split gives versions different traffic volumes.

Winner: winner holds the name of the version that was selected when the test completed. It is
omitted while the test is running and when no winner was determined, for example when the test was
ended without a conclusive result. completedAt is omitted while the test is running.

Scopes:
forms.read

Rate Limiting:
This endpoint is rate limited to 400 requests per minute.