Remove placeholder in strings.xml

Author: abeisgoat

library/src/main/res/values/strings.xml

@@ -1,7 +1,4 @@
 <resources>
     <string name="app_name">FirebaseUI</string>
     <string name="firebaseUrl"></string>
-
-<!-- TODO: Remove or change this placeholder text -->
-    <string name="hello_blank_fragment">Hello blank fragment</string>
 </resources>