update menu colors on the main screen, so we wont forget it in the future

app/src/main/kotlin/com/simplemobiletools/smsmessenger/activities/MainActivity.kt

@@ -100,6 +100,7 @@ class MainActivity : SimpleActivity() {
 
     override fun onCreateOptionsMenu(menu: Menu): Boolean {
         menuInflater.inflate(R.menu.menu_main, menu)
+        updateMenuItemColors(menu)
         return true
     }