[Glitch] Fix background tint in single column light theme

Port 430da03160 to glitch-soc

Signed-off-by: Claire <claire.github-309c@sitedethib.com>

app/javascript/flavours/glitch/styles/components.scss

@@ -2891,7 +2891,7 @@ $ui-header-logo-wordmark-width: 99px;
 }
 
 .tabs-bar__wrapper {
-  background: var(--background-color-tint);
+  background: var(--background-color);
   backdrop-filter: var(--background-filter);
   position: sticky;
   top: $ui-header-height;