[Glitch] Fix very wide images overflowing posts horizontally

Port dde6c28e97ebc697a03d744d78d8822f85cbd6e8 to glitch-soc

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

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

@@ -7555,6 +7555,7 @@ img.modal-warning {
   border-radius: 8px;
   position: relative;
   width: 100%;
+  max-width: 100%;
   min-height: 64px;
   display: grid;
   grid-template-columns: 1fr 1fr;