[Glitch] Make sure the instance banner is never cropped

Port 21209c2b52 to glitch-soc

Signed-off-by: Thibaut Girka <thib@sitedethib.com>

app/javascript/flavours/glitch/styles/widgets.scss

@@ -4,7 +4,6 @@
 
   &__img {
     width: 100%;
-    height: 167px;
     position: relative;
     overflow: hidden;
     border-radius: 4px 4px 0 0;