[web] Clear hardcoded password in external SP auth (#33597)

registerExternalAuthAdmin() now generates a random password on admin registration.

A migration clears the password for existing installs only in CE/SP

GitOrigin-RevId: 94a82d35dc8cd46915c31fb24f477c19367025eb

tools/migrations/package.json

@@ -11,6 +11,7 @@
     "@overleaf/o-error": "workspace:*",
     "@overleaf/promise-utils": "workspace:*",
     "@overleaf/settings": "workspace:*",
+    "bcrypt": "^6.0.0",
     "east": "2.0.3",
     "mongodb": "6.12.0"
   }