Mode 1 with overloader swerve fix #6814 #6801

See if the other vehicle as an overloader, potentially waiting
for us (is near the overload point). We should not swerve as we
need to drive under the pipe of the overloader wagon.

AIDriver.lua

@@ -902,6 +902,7 @@ end
 function AIDriver:getIsInFilltrigger()
 	return self.vehicle.cp.fillTrigger ~= nil or self:isNearFillPoint()
 end
+
 --- Is an alignment course needed to reach waypoint ix in the current course?
 -- override in derived classes as needed
 ---@param course Course

GrainTransportAIDriver.lua

@@ -272,3 +272,13 @@ function GrainTransportAIDriver:delete()
 	end
 	AIDriver.delete(self)
 end
+
+function GrainTransportAIDriver:isProximitySwerveEnabled(vehicle)
+	if vehicle.cp and vehicle.cp.driver and vehicle.cp.driver.is_a(OverloaderAIDriver) then
+		-- the other vehicle as an overloader, potentially waiting for us. We should not swerve
+		-- as we need to drive under the pipe of the overloader wagon
+		return not vehicle.cp.driver:isNearOverloadPoint()
+	else
+		return true
+	end
+end

OverloaderAIDriver.lua

@@ -187,3 +187,8 @@ end
 function OverloaderAIDriver:enableFillTypeUnloading()
 
 end
+
+--- Is around the overload point?
+function OverloaderAIDriver:isNearOverloadPoint()
+	return self.nearOverloadPoint
+end