Refines the animated image to fit the screen display.

Root cause:
The width and height of animated image are wrap_content. It causes the gif or drawable which are non-transparent background to have a little weird display under dark mode.

Next:
1. Revise the width from wrap_content to match_parent, and add the fit center scale type.
2. Correct the function usage

Bug: 155946967
Test: manual test
Change-Id: I7470efb945a2b3bedb695e1b6f34475c6f190f9d

res/layout/preference_animated_image.xml

@@ -24,9 +24,10 @@
 
     <ImageView
         android:id="@+id/animated_img"
-        android:layout_width="wrap_content"
+        android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:layout_gravity="center"
+        android:scaleType="fitCenter"
         android:focusable="false"
         android:clickable="false"
         android:adjustViewBounds="true"/>

src/com/android/settings/accessibility/AnimatedImagePreference.java

@@ -60,7 +60,7 @@ public class AnimatedImagePreference extends Preference {
         }
 
         if (mMaxHeight > -1) {
-            imageView.setMaxWidth(mMaxHeight);
+            imageView.setMaxHeight(mMaxHeight);
         }
     }