refactor(es_extended/server/functions): move GetExtendedVehicleFromPlate plate validation to vehicle class

[core]/es_extended/server/classes/vehicle.lua

@@ -71,6 +71,8 @@ Core.vehicleClass = {
 		return obj
 	end,
 	getFromPlate = function(plate)
+		assert(type(plate) == "string", "Expected 'plate' to be a string")
+
 		if Core.vehicles[plate] then
 			local obj = table.clone(Core.vehicleClass)
 			obj.plate = plate

[core]/es_extended/server/functions.lua

@@ -627,7 +627,5 @@ end
 ---@param plate string
 ---@return VehicleClass?
 function ESX.GetExtendedVehicleFromPlate(plate)
-    assert(type(plate) == "string", "Expected 'plate' to be a string")
-
    return Core.vehicleClass.getFromPlate(plate)
 end