Revert "[GH-5915] Clicking on @mention of a user in a post shows the profile popover (#6129)" (#6289)

This reverts commit 83f819451a.

webapp/package.json

@@ -15,7 +15,6 @@
     "flux": "3.1.2",
     "font-awesome": "4.7.0",
     "highlight.js": "9.10.0",
-    "html-to-react": "1.2.7",
     "inobounce": "0.1.4",
     "intl": "1.2.5",
     "jasny-bootstrap": "3.1.3",