chore: Replace packages with native functions (#5140)

app/javascript/dashboard/helper/flag.js

@@ -0,0 +1,19 @@
+const FLAG_OFFSET = 127397;
+
+/**
+ * Gets emoji flag for given locale.
+ *
+ * @param {string} countryCode locale code
+ * @return {string} emoji flag
+ *
+ * @example
+ * getCountryFlag('cz') // '🇨🇿'
+ */
+export const getCountryFlag = countryCode => {
+  const codePoints = countryCode
+    .toUpperCase()
+    .split('')
+    .map(char => FLAG_OFFSET + char.charCodeAt());
+
+  return String.fromCodePoint(...codePoints);
+};