e2e: add tests for translations (#114390)

e2e: add tests for translations

e2e-playwright/test-plugins/grafana-test-datasource/i18next.config.ts

@@ -0,0 +1,13 @@
+import { defineConfig } from 'i18next-cli';
+import pluginJson from './plugin.json';
+
+export default defineConfig({
+  locales: pluginJson.languages,
+  extract: {
+    input: ['**/*.{tsx,ts}'],
+    output: 'locales/{{language}}/{{namespace}}.json',
+    defaultNS: pluginJson.id,
+    functions: ['t', '*.t'],
+    transComponents: ['Trans'],
+  },
+});