Fix extended video player (gifv) modal size

It was currently full-size

app/javascript/flavours/glitch/styles/components/media.scss

@@ -161,6 +161,12 @@
   max-width: 100vw;
   max-height: 100vh;
   position: relative;
+}
+
+.media-modal {
+  width: 100%;
+  height: 100%;
+  position: relative;
 
   .extended-video-player {
     width: 100%;
@@ -176,12 +182,6 @@
   }
 }
 
-.media-modal {
-  width: 100%;
-  height: 100%;
-  position: relative;
-}
-
 .media-modal__closer {
   position: absolute;
   top: 0;