[Rspamd] Remove MX check overrides that rspamd ignores

data/conf/rspamd/local.d/groups.conf

@@ -23,24 +23,6 @@ symbols {
   }
 }
 
-group "MX" {
-  "MX_INVALID" {
-    score = 0.5;
-    description = "No connectable MX";
-    one_shot = true;
-  }
-  "MX_MISSING" {
-    score = 2.0;
-    description = "No MX record";
-    one_shot = true;
-  }
-  "MX_GOOD" {
-    score = -0.01;
-    description = "MX was ok";
-    one_shot = true;
-  }
-}
-
 group "reputation" {
   symbols = {
     "IP_REPUTATION_HAM" {