Insights/fix commits before index

Created by: coury-clark

Fixes #30434 (closed)

In our compression logic we assumed that the index would always include enough history to evaluate each commit from oldest to youngest. In 3.35 we enabled editable series intervals for all repos series, which allows them to extend beyond the horizon of the index history. This PR adds some logic to ensure that we are only compressing commits within the range of the index.