Remove insights (#23952)

* removed server side

* Updated store layer

* unused import

* Updated autogenerated code template

* Updated tests

* lint fix

* unused translations

* webapp side

* Updated i18n

* lint fix:

* type fix

* Updated snapshots

* Removed insights from API specs

* updated e2e

* Updated e2e tests

* Updated e2e tests

* Removed insights tests

* Removed Insights as possible channel to load in sidebar from test

* Removed more insights tests

* More e2e fixed

* More cleanup

* Lint

* More cleanup in client4 and boards api

* More cleanup

* Fixes

* lint fix

---------

Co-authored-by: maria.nunez <maria.nunez@mattermost.com>
Co-authored-by: Mattermost Build <build@mattermost.com>

server/i18n/de.json

@@ -9466,10 +9466,6 @@
     "id": "api.team.invite_guests_to_channels.disabled.error",
     "translation": "Gastkonten sind deaktiviert"
   },
-  {
-    "id": "model.insights.get_start_of_day_for_time_range.time_range.app_error",
-    "translation": "Ungültiger Zeitbereich."
-  },
   {
     "id": "app.collection.add_topic.exists.app_error",
     "translation": "Thementyp existiert schon."