Fix scroll thumb visibility issue

Fix a problem where the scroll thumb would briefly show up when SongsFragment is first shown.

app/src/main/AndroidManifest.xml

@@ -22,6 +22,7 @@
             android:icon="@mipmap/ic_launcher"
             android:launchMode="singleInstance"
             android:roundIcon="@mipmap/ic_launcher_round"
+            android:exported="true"
             android:windowSoftInputMode="adjustPan">
 
             <intent-filter>

app/src/main/java/org/oxycblt/auxio/songs/CobaltScrollThumb.kt

@@ -66,7 +66,12 @@ class CobaltScrollThumb @JvmOverloads constructor(
             }
         }
 
+        isVisible = false
         isActivated = false
+
+        post {
+            isVisible = true
+        }
     }
 
     /**