fix: invalid JSON in FR and DE translations (#9803)

* fix: invalid JSON in FR translation

* fix: broken or misformatted translations and add unit test for JSON validty

* Move translation lint test to CI task

.github/workflows/superset-translations.yml

@@ -0,0 +1,19 @@
+name: Translations
+
+on: [push, pull_request]
+
+jobs:
+  frontend-build:
+    name: build
+    runs-on: ubuntu-18.04
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v2
+    - name: Install dependencies
+      uses: apache-superset/cached-dependencies@adc6f73
+      with:
+        run: npm-install
+    - name: lint
+      working-directory: ./superset-frontend
+      run: |
+        npm run check-translation

superset-frontend/package.json

@@ -21,7 +21,9 @@
     "lint": "eslint --ignore-path=.eslintignore --ext .js,.jsx,.ts,.tsx . && npm run type",
     "prettier-check": "prettier --check '{src,stylesheets}/**/*.{css,less,sass,scss}'",
     "lint-fix": "eslint --fix --ignore-path=.eslintignore --ext .js,.jsx,.ts,tsx . && npm run clean-css && npm run type",
-    "clean-css": "prettier --write '{src,stylesheets}/**/*.{css,less,sass,scss}'"
+    "clean-css": "prettier --write '{src,stylesheets}/**/*.{css,less,sass,scss}'",
+    "check-translation": "prettier --check ../superset/translations/**/LC_MESSAGES/*.json",
+    "clean-translation": "prettier --write ../superset/translations/**/LC_MESSAGES/*.json"
   },
   "repository": {
     "type": "git",

superset/translations/en/LC_MESSAGES/messages.json

@@ -1 +1,12 @@
-{"domain":"superset","locale_data":{"superset":{"":{"domain":"superset","plural_forms":"nplurals=2; plural=(n != 1)","lang":"en"}}}}
+{
+  "domain": "superset",
+  "locale_data": {
+    "superset": {
+      "": {
+        "domain": "superset",
+        "plural_forms": "nplurals=2; plural=(n != 1)",
+        "lang": "en"
+      }
+    }
+  }
+}