Adjust message bubble tail position

It should align with the center of the avatar.

stylesheets/_conversation.scss

@@ -119,13 +119,13 @@
     }
 
     &::before {
-      top: (44px / 2) - 8px;
+      top: (34px / 2) - 8px;
       border-top: 8px solid transparent;
       border-bottom: 8px solid transparent;
     }
 
     &::after {
-      top: (44px / 2) - 6px;
+      top: (34px / 2) - 6px;
       border-top: 6px solid transparent;
       border-bottom: 6px solid transparent;
     }

stylesheets/manifest.css

@@ -370,12 +370,12 @@ input.new-message {
       width: 0; }
     .message-detail .bubble::before,
     .message-list .bubble::before {
-      top: 14px;
+      top: 9px;
       border-top: 8px solid transparent;
       border-bottom: 8px solid transparent; }
     .message-detail .bubble::after,
     .message-list .bubble::after {
-      top: 16px;
+      top: 11px;
       border-top: 6px solid transparent;
       border-bottom: 6px solid transparent; }
   .message-detail .incoming .bubble,