In-browser editor's commit message dialogue doesn't support non-latin characters

Summary

When committing a change made via the new in-browser editor, the commit message dialogue doesn't correctly handle non-latin characters.

Steps to Reproduce

1. Edit any text file using the in-browser editor feature
2. Commit your changes, and use the following commit message: "Вы столкнулись с ошибкой"

Expected Results

In the Commits tab, the message should be rendered correctly

Actual Results

This example message is rendered as "Ð’Ñ‹ столкнулись с ошибкой"

Workaround

Commits made from other sources (e.g. from your local copy and pushed to Bitbucket) are displayed correctly