Tabbed bottom sheet adjustments (#6309)

* SimpleNavigationView: Don't set background and elevation

* Add divider for tabs in bottom sheet

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

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
+    <item>
+        <shape
+            android:shape="rectangle">
+            <solid android:color="@android:color/transparent"/>
+        </shape>
+    </item>
+    <item
+        android:gravity="bottom">
+        <shape>
+            <size android:height="1dp" />
+            <solid android:color="?attr/colorSurfaceVariant" />
+        </shape>
+    </item>
+</layer-list>

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

@@ -12,11 +12,10 @@
 
         <!-- Remove background color so rounded sheet corners work -->
         <com.google.android.material.tabs.TabLayout
-            style="@style/Widget.Tachiyomi.TabLayout"
             android:id="@+id/tabs"
             android:layout_width="0dp"
             android:layout_height="wrap_content"
-            android:background="@android:color/transparent"
+            android:background="@drawable/transparent_tabs_background"
             app:layout_constraintBottom_toBottomOf="parent"
             app:layout_constraintEnd_toStartOf="@+id/menu"
             app:layout_constraintStart_toStartOf="parent"

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

@@ -4,7 +4,6 @@
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="?attr/listPreferredItemHeightSmall"
-    android:background="?android:attr/colorBackground"
     android:gravity="center_vertical"
     android:orientation="horizontal"
     android:paddingStart="?attr/listPreferredItemPaddingStart"