Identify the last good echo in adaptive mask instead of sum of good echoes

[tsalo]

Closes https://github.com/ME-ICA/tedana/issues/679. I built this off of #1060 and #1057, so it shares many changes.

This will only ever increase the adaptive mask value, as the last good echo will always be equal to, or higher than, the total number of good echoes.

Note that this does not identify the last contiguous good echo (i.e., the last good echo before any bad echoes). Therefore, if you have something like [good, bad, good, bad], the result with be 3, not 1.

Changes proposed in this pull request:

• Identify the last good echo for the adaptive mask, instead of the total number of good echoes.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 89.80%. Comparing base (461bc38) to head (2d3712a). Report is 2 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1061 +/- ## ======================================= Coverage 89.79% 89.80% ======================================= Files 26 26 Lines 3537 3540 +3 Branches 620 621 +1 ======================================= + Hits 3176 3179 +3 Misses 212 212 Partials 149 149 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.