[Glitch] Fix the appearance of avatars when they do not load

Port 8b70834035 to glitch-soc

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

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

@@ -2196,13 +2196,14 @@ body > [data-popper-placement] {
   display: block;
   position: relative;
   border-radius: var(--avatar-border-radius);
+  background-color: var(--surface-background-color);
 
   img {
-    display: block;
     width: 100%;
     height: 100%;
     object-fit: cover;
     border-radius: var(--avatar-border-radius);
+    display: inline-block; // to not show broken images
   }
 
   &-inline {