Try to show actual path in invalid location downloader notification

Instead of the class/hashCode, which doesn't mean much to a user.

(cherry picked from commit 83130f9bf964dfce512c77803f8b5bcfb90c8f08)

core/src/main/java/tachiyomi/core/storage/UniFileExtensions.kt

@@ -13,6 +13,9 @@ val UniFile.extension: String?
 val UniFile.nameWithoutExtension: String?
     get() = name?.substringBeforeLast('.')
 
+val UniFile.displayablePath: String
+    get() = filePath ?: uri.toString()
+
 fun UniFile.toTempFile(context: Context): File {
     val inputStream = context.contentResolver.openInputStream(uri)!!
     val tempFile = File.createTempFile(