It looks like you have recurring malware issue. Checked the link you have provided, the harmful js script are found under theme header file (wp-content/themes/theme_name/header.php). This type of js script hosts a malicious url which is blacklisted by Google. Since the link keeps appearing in the website file, there may be other malicious script or file among your website files which is injecting this js script into the header files. You can use any rated security plugin like Wordfence to know more about malicious file. If it doesn't help then you may need to contact vendor who can manually check and fix the site one like our self.
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