Skip empty rows in the list of target websites #59
Description
When the list of target websites to monitor is updated to make the list shorter, an error is thrown:
Exception: 指定された属性に値がありません: url
at targetWebsites.reduce.newErrors (websiteMonitoring:448:23)
at Array.reduce (<anonymous>)
at websiteMonitoring (websiteMonitoring:433:39)
at websiteMonitoringTriggered (websiteMonitoring:300:3)
at __GS_INTERNAL_top_function_call__.gs:1:8