Fix style for qr code

stylesheets/_conversation.scss

@@ -89,6 +89,9 @@
     text-align: center;
     padding: 25px;
     margin: 10px auto;
+    canvas {
+      display: none;
+    }
     img {
       display: inline-block;
       max-width: 100%;

stylesheets/manifest.css

@@ -990,6 +990,8 @@ input.search {
   text-align: center;
   padding: 25px;
   margin: 10px auto; }
+  .key-verification .qr canvas {
+    display: none; }
   .key-verification .qr img {
     display: inline-block;
     max-width: 100%; }