Add card image background color

app/src/main/res/drawable/shape_card_image_background.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <shape xmlns:android="http://schemas.android.com/apk/res/android"
     android:shape="rectangle">
+    <solid android:color="?attr/cardImageBackground" />
     <corners android:radius="?attr/cardRounding" />
 </shape>

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

@@ -28,7 +28,7 @@
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:adjustViewBounds="true"
-            android:background="@drawable/transparent_card_border"
+            android:background="@drawable/shape_card_image_background"
             android:contentDescription="@null"
             android:scaleType="centerCrop"
             lb:layout_viewType="main"

app/src/main/res/values/attrs.xml

@@ -12,6 +12,7 @@
         <!-- Popup Window Attributes -->
         <attr name="popupWindowBackground" format="reference|color" />
         <!-- CardView Attributes -->
+        <attr name="cardImageBackground" format="reference|color" />
         <attr name="cardViewBackground" format="reference|color" />
         <!-- Theme Attributes -->
         <attr name="cardRounding" format="dimension" />

app/src/main/res/values/theme_jellyfin.xml

@@ -11,6 +11,7 @@
         <!-- Background color for popup windows -->
         <item name="popupWindowBackground">@color/not_quite_black</item>
         <!-- Background color for CardViews -->
+        <item name="cardImageBackground">@color/grey</item>
         <item name="cardViewBackground">@android:color/transparent</item>
         <!-- Search FAB color -->
         <item name="defaultSearchColor">@color/jellyfin_blue</item>