also extract this one...

src/main/java/com/owncloud/android/authentication/AuthenticatorActivity.java

@@ -417,7 +417,7 @@ public class AuthenticatorActivity extends AccountAuthenticatorActivity
         new Handler().postDelayed(new Runnable() {
             @Override
             public void run() {
-                Snackbar.make(mLoginWebView, "Go back to old login method", Snackbar.LENGTH_INDEFINITE)
+                Snackbar.make(mLoginWebView, R.string.fallback_weblogin_text, Snackbar.LENGTH_INDEFINITE)
                         .setAction(R.string.fallback_weblogin_back, new View.OnClickListener() {
                             @Override
                             public void onClick(View v) {

src/main/res/values/strings.xml

@@ -694,4 +694,5 @@
     <string name="whats_new_fingerprint_title">Unlock with fingerprint</string>
     <string name="whats_new_fingerprint_content">Use your fingerprint to unlock the app</string>
     <string name="fallback_weblogin_back">BACK</string>
+    <string name="fallback_weblogin_text">Go back to old login method</string>
 </resources>