[🔥AUDIT🔥] Export some Flow types from the i18n package. (#223)

🖍 _This is an audit!_ 🖍

## Summary:
This is needed by some code in Webapp.

Issue: FEI-4434

## Test plan:

Author: jeresig

Auditors: kevinbarabash

Required Reviewers: 

Approved By: kevinbarabash

Checks: ❌ Test (macOS-latest, 16.x), ✅ Test (macOS-latest, 12.x), ✅ Test (ubuntu-latest, 12.x), ✅ codecov/project, ✅ CodeQL, ✅ Lint, flow, and coverage check (ubuntu-latest, 16.x), ⏭  dependabot, ✅ gerald, ✅ Analyze (javascript), ✅ Prime node_modules cache for primary configuration (ubuntu-latest, 16.x)

Pull Request URL: #223

.changeset/two-pans-fail.md

@@ -0,0 +1,5 @@
+---
+"@khanacademy/wonder-stuff-i18n": minor
+---
+
+Export some Flow types from the i18n package.

packages/wonder-stuff-i18n/src/index.js

@@ -12,3 +12,6 @@ export {
     translateString,
 } from "./utils/i18n-utils.js";
 export {getEmojiForLocale} from "./utils/emoji-for-locale.js";
+
+export type {ExtractedString} from "./utils/extract-i18n.js";
+export type {TranslatedLocaleStrings} from "./utils/i18n-utils.js";