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>

e2e-tests/cypress/tests/support/api/preference.js

@@ -426,12 +426,6 @@ Cypress.Commands.add('apiDisableTutorials', (userId) => {
             name: 'actions_menu_tutorial_state',
             value: '{"actions_menu_modal_viewed":true}',
         },
-        {
-            user_id: userId,
-            category: 'insights',
-            name: 'insights_tutorial_state',
-            value: '{"insights_modal_viewed":true}',
-        },
         {
             user_id: userId,
             category: 'drafts',