DEV: Move discourse-chat to the core repo. (#18776)

As part of this move, we are also renaming `discourse-chat` to `chat`.

plugins/chat/lib/secure_uploads_compatibility.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+class Chat::SecureUploadsCompatibility
+  ##
+  # At this point in time, secure uploads is not compatible with chat,
+  # so if it is enabled then chat uploads must be disabled to avoid undesirable
+  # behaviour.
+  #
+  # The env var DISCOURSE_ALLOW_UNSECURE_CHAT_UPLOADS can be set to keep
+  # it enabled, but this is strongly advised against.
+  def self.update_settings
+    if SiteSetting.secure_uploads && SiteSetting.chat_allow_uploads &&
+         !GlobalSetting.allow_unsecure_chat_uploads
+      SiteSetting.chat_allow_uploads = false
+      StaffActionLogger.new(Discourse.system_user).log_site_setting_change(
+        "chat_allow_uploads",
+        true,
+        false,
+        context: "Disabled because secure_uploads is enabled",
+      )
+    end
+  end
+end