MDL-64017 core: remove group conversation check for processors

We now want to allow processors to process group messages.

lib/classes/message/manager.php

@@ -202,10 +202,9 @@ class manager {
             }
 
             // Fill in the array of processors to be used based on default and user preferences.
-            // This applies only to individual conversations. Messages to group conversations ignore processors.
             // Do not process muted conversations.
             $processorlist = [];
-            if ($conv->type == \core_message\api::MESSAGE_CONVERSATION_TYPE_INDIVIDUAL && !$recipient->ismuted) {
+            if (!$recipient->ismuted) {
                 foreach ($processors as $processor) {
                     // Skip adding processors for internal user, if processor doesn't support sending message to internal user.
                     if (!$usertoisrealuser && !$processor->object->can_send_to_any_users()) {