fix(i18n): Change Bengali locale code from 'be' to 'bn'

[adi-ray]

Fixes #3601 (comment)

Changes:
Changed Bengali locale code from be (Belarusian) to bn (Bengali).

I have verified that this pull request:

• has no linting errors (npm run lint)
• has no test errors (npm run test)
• is from a uniquely-named feature branch and is up to date with the develop branch.
• is descriptively named and links to an issue number, i.e. Fixes #123

[raclim]

Thanks so much for the quick fix!