Posthog: drop $initial_person_info from outgoing events (#3968)

* Posthog: drop $initial_person_info from outgoing events

* Posthog: migrate from sanitize_properties to before_send

* strip URL fields from $set / $set_once

* enable mask_personal_data_properties

* review

* update tests to check for `delete` (not anymore `=null`)
rename: `applyPrivacyFilters`->`santizeSensitiveData`

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Co-authored-by: Timo K <toger5@hotmail.de>

package.json

@@ -118,7 +118,7 @@
     "pako": "^2.0.4",
     "postcss": "^8.4.41",
     "postcss-preset-env": "^10.0.0",
-    "posthog-js": "1.160.3",
+    "posthog-js": "1.374.0",
     "prettier": "^3.0.0",
     "qrcode": "^1.5.4",
     "react": "19",