Fix broken startup-css-check

Likely caused by merge timing issue from [this MR][1].

[1]: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/62866

app/assets/stylesheets/startup/startup-dark.scss

@@ -546,6 +546,12 @@ body {
   color: #dbdbdb;
   vertical-align: baseline;
 }
+img.emoji {
+  height: 20px;
+  vertical-align: top;
+  width: 20px;
+  margin-top: 1px;
+}
 .chart {
   overflow: hidden;
   height: 220px;

app/assets/stylesheets/startup/startup-general.scss

@@ -530,6 +530,12 @@ body {
   color: #525252;
   vertical-align: baseline;
 }
+img.emoji {
+  height: 20px;
+  vertical-align: top;
+  width: 20px;
+  margin-top: 1px;
+}
 .chart {
   overflow: hidden;
   height: 220px;

ee/app/assets/stylesheets/startup/startup-dark.scss

@@ -546,6 +546,12 @@ body {
   color: #dbdbdb;
   vertical-align: baseline;
 }
+img.emoji {
+  height: 20px;
+  vertical-align: top;
+  width: 20px;
+  margin-top: 1px;
+}
 .chart {
   overflow: hidden;
   height: 220px;

ee/app/assets/stylesheets/startup/startup-general.scss

@@ -530,6 +530,12 @@ body {
   color: #525252;
   vertical-align: baseline;
 }
+img.emoji {
+  height: 20px;
+  vertical-align: top;
+  width: 20px;
+  margin-top: 1px;
+}
 .chart {
   overflow: hidden;
   height: 220px;