chore(dependencies): update package-lock.json for dottie, dompurify, and immutable

- Bumped dottie version from 2.0.6 to 2.0.7.
- Updated dompurify from 3.3.1 to 3.3.2, adding node engine compatibility.
- Upgraded immutable from 5.1.3 to 5.1.5.

backend/package-lock.json

@@ -1612,9 +1612,9 @@
       }
     },
     "node_modules/dottie": {
-      "version": "2.0.6",
-      "resolved": "https://registry.npmjs.org/dottie/-/dottie-2.0.6.tgz",
-      "integrity": "sha512-iGCHkfUc5kFekGiqhe8B/mdaurD+lakO9txNnTvKtA6PISrw86LgqHvRzWYPyoE2Ph5aMIrCw9/uko6XHTKCwA==",
+      "version": "2.0.7",
+      "resolved": "https://registry.npmjs.org/dottie/-/dottie-2.0.7.tgz",
+      "integrity": "sha512-7lAK2A0b3zZr3UC5aE69CPdCFR4RHW1o2Dr74TqFykxkUCBXSRJum/yPc7g8zRHJqWKomPLHwFLLoUnn8PXXRg==",
       "license": "MIT"
     },
     "node_modules/dunder-proto": {