Update message_avatar.xml

rocket-chat-android-widgets/src/main/res/layout/message_avatar.xml

 <?xml version="1.0" encoding="utf-8"?>
 <com.facebook.drawee.view.SimpleDraweeView xmlns:android="http://schemas.android.com/apk/res/android"
-        xmlns:fresco="http://schemas.android.com/apk/res-auto"
-        android:id="@+id/drawee_avatar"
-        android:layout_width="match_parent"
-        android:layout_height="match_parent"
-        fresco:actualImageScaleType="fitCenter"
-        fresco:roundedCornerRadius="5dp" />
\ No newline at end of file
+  xmlns:fresco="http://schemas.android.com/apk/res-auto"
+  android:id="@+id/drawee_avatar"
+  android:layout_width="match_parent"
+  android:layout_height="match_parent"
+  fresco:actualImageScaleType="fitXY"
+  fresco:roundedCornerRadius="5dp" />
\ No newline at end of file