Simplify emoji rendering

It seems like most of our custom styles around the .emoji class are
useless and we can just make them render like any other text.

Fixes: go-gitea#34019

Author: silverwind

web_src/css/base.css

@@ -989,14 +989,6 @@ table th[data-sortt-desc] .svg {
   box-shadow: 0 0 0 1px var(--color-secondary) inset;
 }
 
-.emoji {
-  font-size: 1.25em;
-  line-height: var(--line-height-default);
-  font-style: normal !important;
-  font-weight: var(--font-weight-normal) !important;
-  vertical-align: -0.075em;
-}
-
 .emoji img {
   border-width: 0 !important;
   margin: 0 !important;

web_src/css/markup/content.css

@@ -338,7 +338,6 @@
 
 .markup .emoji {
   max-width: none;
-  vertical-align: text-top;
 }
 
 .markup span.frame {