MM-45899: Insights: least active channels (#20796)

* Add api endpoints, app layers for top inactive channels with dummy store calls

* Add store functions for top inactive channels

* Add model, store, app tests.

* Add client function and api tests

* Add participants information to TopInactiveChannel

* Translation fix

* Style fix while writing response

* Return channelmember IDs instead of profiles, query in batch avoiding inside the loop

* Make the following changes

 - move DeleteAt to subqueries, to avoid select, group by
 - Remove TeamId from response
 - Count bots and webhook posts

* SQL query lint fix, store test fix to include bot messages

* make app-layers

* Fix empty participant lists being sent as [""]

* Track channel joins, to distinguish 0 activity channels vs new channels

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

i18n/en.json

@@ -4539,6 +4539,14 @@
     "id": "app.channel.get_top_for_user_since.app_error",
     "translation": " "
   },
+  {
+    "id": "app.channel.get_top_invalid_for_team_since.app_error",
+    "translation": " "
+  },
+  {
+    "id": "app.channel.get_top_invalid_for_user_since.app_error",
+    "translation": " "
+  },
   {
     "id": "app.channel.get_unread.app_error",
     "translation": "Unable to get the channel unread messages."