FEAT: Allow admin delete user's associated accounts (#29018)

This commit introduces a feature that allows an admin to delete a user's
associated account. After deletion, a log will be recorded in staff
actions.

ref=t/136675

config/locales/client.en.yml

@@ -6346,6 +6346,7 @@ en:
             tag_group_create: "create tag group"
             tag_group_destroy: "delete tag group"
             tag_group_change: "change tag group"
+            delete_associated_accounts: "delete associated accounts"
         screened_emails:
           title: "Screened Emails"
           description: "When someone tries to create a new account, the following email addresses will be checked and the registration will be blocked, or some other action performed."
@@ -6575,6 +6576,9 @@ en:
         check_sso:
           title: "Reveal SSO payload"
           text: "Show"
+        delete_associated_accounts:
+          title: "Delete all associated accounts for this user"
+          text: "Delete associated accounts"
 
       user:
         suspend_failed: "Something went wrong suspending this user %{error}"
@@ -6692,6 +6696,7 @@ en:
         post_edits_count: "Post Edits"
         anonymize: "Anonymize User"
         anonymize_confirm: "Are you SURE you want to anonymize this account? This will change the username and email, and reset all profile information."
+        delete_associated_accounts_confirm: "Are you SURE you want to delete associated accounts from this account? They may not be able to log in."
         anonymize_yes: "Yes, anonymize this account"
         anonymize_failed: "There was a problem anonymizing the account."
         delete: "Delete User"

config/routes.rb

@@ -162,6 +162,7 @@ Discourse::Application.routes.draw do
         put "disable_second_factor"
         delete "sso_record"
         get "similar-users.json" => "users#similar_users"
+        put "delete_associated_accounts"
       end
       get "users/:id.json" => "users#show", :defaults => { format: "json" }
       get "users/:id/:username" => "users#show",