Allow the application to work without en.json file in dev environment

packages/app/services/i18n/i18n.ts

@@ -72,6 +72,7 @@ class I18N {
         locale: string;
         messages: Record<string, string>;
     }> {
+        try {
             const [{ default: messages }] = await Promise.all([
                 import(/* webpackChunkName: "locale-[request]" */ `app/i18n/${locale}.json`),
                 intlPolyfill(locale),
@@ -81,6 +82,25 @@ class I18N {
                 locale,
                 messages,
             };
+        } catch (err) {
+            if (process.env.NODE_ENV !== 'production') {
+                if (err.message === "Cannot find module './en.json'") {
+                    console.warn(
+                        [
+                            "Locales module for the source language isn't exists.",
+                            'You may generate this file by running yarn i18n:extract command.',
+                            'Until then, defaultMessages will be used for displaying on the site.',
+                        ].join(' '),
+                    );
+                } else {
+                    console.error(err);
+                }
+
+                return { locale, messages: {} };
+            }
+
+            throw err;
+        }
     }
 }