Remove backgrounds from list picker items

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

@@ -30,6 +30,7 @@
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:layout_alignParentStart="true"
+    android:background="@null"
     android:layout_gravity="center_vertical"
     android:alpha="@dimen/alpha_secondary"
     android:scaleType="center"/>
@@ -41,6 +42,7 @@
     android:layout_centerVertical="true"
     android:layout_toEndOf="@id/icon"
     android:layout_toStartOf="@id/size"
+    android:background="@null"
     android:paddingStart="@dimen/keyline_second"
     android:paddingEnd="@dimen/keyline_first"
     android:checkMark="@drawable/checkmark"

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

@@ -25,6 +25,7 @@
       android:paddingTop="8dp"
       android:paddingBottom="8dp"
       android:paddingStart="0dp"
+      android:background="@null"
       android:paddingEnd="@dimen/keyline_first"
       android:alpha="@dimen/alpha_secondary"
       android:clickable="true"
@@ -39,6 +40,7 @@
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       android:ellipsize="end"
+      android:background="@null"
       android:textColor="@color/text_secondary"
       android:fontFamily="@string/font_fontFamily_medium"
       android:layout_alignParentStart="true"