Fix various CodeClimate warnings

app/javascript/styles/mastodon/admin.scss

@@ -459,22 +459,6 @@ body,
   }
 }
 
-.flavour-screen {
-  display: block;
-  margin: 10px auto;
-  max-width: 100%;
-}
-
-.flavour-description {
-  display: block;
-  font-size: 16px;
-  margin: 10px 0;
-
-  & > p {
-    margin: 10px 0;
-  }
-}
-
 .report-accounts {
   display: flex;
   flex-wrap: wrap;