Move error check to pvt

app/services/merge_requests/merge_base_service.rb

@@ -8,10 +8,6 @@ module MergeRequests
 
     attr_reader :merge_request
 
-    # Overridden in EE.
-    def error_check!
-    end
-
     # Overridden in EE.
     def hooks_validation_pass?(_merge_request)
       true
@@ -19,6 +15,7 @@ module MergeRequests
 
     # Overridden in EE.
     def hooks_validation_error(_merge_request)
+      # No-op
     end
 
     def source
@@ -31,6 +28,11 @@ module MergeRequests
 
     private
 
+    # Overridden in EE.
+    def error_check!
+      # No-op
+    end
+
     def raise_error(message)
       raise MergeError, message
     end