Merge pull request #9747 from overleaf/ii-cm6-grammarly-dark-theme-css-fix

[web] Grammarly suggestions underline css fix

GitOrigin-RevId: 195cf787cf9b3c8a7843ba15e2ed59320942a64e

services/web/frontend/stylesheets/app/grammarly.less

@@ -1,3 +1,3 @@
 grammarly-extension {
-  mix-blend-mode: normal;
+  mix-blend-mode: normal !important;
 }