Investigate behavior of updating translation stats

Right now the behavior seems incorrect. @KatieWoe pointed this out to me in her testing of https://github.com/phetsims/qa/issues/931.

I think it would be a good idea to break this problem down into smaller problems:

When does the "(pending update)" badge appear?

1. If you translate a sim-specific string, does the "(pending update)" badge appear next to the sim?
2. If you translate a shared string, does the "(pending update)" badge appear next to the sim and the other sims that share the string?
3. If you translate a common string, do all sims that have the common string have a "(pending update)" badge?

How long does it take for the stats to update?

At this point, the only bottleneck for having perfectly up-to-date translation stats is the build server. We can get fresh sim metadata (since we bust the cache) and we can get fresh GitHub data (since we are now using Octokit).

1. If you translate a sim-specific string, how long does it take for the stats to update?
2. If you translate a shared string, how long does it take for the stats to update?
3. If you translate a common string, how long does it take for the stats to update?

Start by reproducing the sim-specific, shared, and common-string translation scenarios described in the issue, using the behavior reported in QA issue 931 as context. Measure how long each case takes for the “pending update” badge and translation stats to change; done means the affected sims and update timing are documented and the incorrect behavior is narrowed to the relevant part of the application.