Remove transition for cards' background color

It makes theme changes weird (cards' backgrounds is the only thing that
is animated) and it makes outgoing cards' backgrounds opaque while they
are moving.

Author: eltoder

src/components/ResponsiveSetCard.js

@@ -17,8 +17,7 @@ const useStyles = makeStyles((theme) => ({
     justifyContent: "center",
     flexShrink: 0,
     backgroundColor: theme.setCard.background,
-    transition:
-      "box-shadow 0.15s, width 0.5s, height 0.5s, background-color 0.3s",
+    transition: "box-shadow 0.15s, width 0.5s, height 0.5s",
   },
   clickable: {
     cursor: "pointer",