move styles for download widget to default.css file

assets/css/default.css

@@ -767,3 +767,7 @@ h1, h2, h3, h4, h5, p,
 .channel-emoji {
   margin: 0 2px;
 }
+
+#download_widget {
+    width: 100%;
+}

assets/css/download-widget.css

@@ -1,3 +0,0 @@
-#download_widget {
-    width: 100%;
-}

src/invidious/views/watch.ecr

@@ -28,7 +28,6 @@
 <meta name="twitter:player:height" content="720">
 <link rel="alternate" href="https://www.youtube.com/watch?v=<%= video.id %>">
 <%= rendered "components/player_sources" %>
-<link rel="stylesheet" href="/css/download-widget.css">
 <title><%= title %> - Invidious</title>
 
 <!-- Description expansion also updates the 'Show more' button to 'Show less' so