Resize chat headline to 18sp

Signed-off-by: Andy Scherzinger <info@andy-scherzinger.de>

app/src/main/res/layout/activity_chat.xml

@@ -88,7 +88,7 @@
                     android:lines="1"
                     android:text="@string/nc_app_product_name"
                     android:textColor="@color/fontAppbar"
-                    android:textSize="22sp" />
+                    android:textSize="18sp" />
 
                 <androidx.emoji2.widget.EmojiTextView
                     android:id="@+id/chat_toolbar_status_message"