Medianet: Sanitize usersync iframe url (#4128)

Author: rishi-parmar

static/bidder-info/medianet.yaml

@@ -20,7 +20,7 @@ capabilities:
       - native
 userSync:
   iframe:
-    url: https://hbx.media.net/checksync.php?cid=8CUEHS6F9&cs=87&type=mpbc&cv=37&vsSync=1&uspstring={{.USPrivacy}}&gdpr={{.GDPR}}&gdprsting={{.GDPRConsent}}&gpp={{.GPP}}&gpp_sid={{.GPPSID}}&redirect={{.RedirectURL}}
+    url: https://hbx.media.net/checksync.php?cid=8CUEHS6F9&cs=87&type=mpbc&cv=37&vsSync=1&uspstring={{.USPrivacy}}&gdpr={{.GDPR}}&gdprstring={{.GDPRConsent}}&gpp={{.GPP}}&gpp_sid={{.GPPSID}}&redirect={{.RedirectURL}}
     userMacro: "<vsid>"
   redirect:
     url: https://hbx.media.net/cksync.php?cs=1&type=pbs&ovsid=setstatuscode&bidder=medianet&gdpr={{.GDPR}}&gdpr_consent={{.GDPRConsent}}&us_privacy={{.USPrivacy}}&redirect={{.RedirectURL}}&gpp={{.GPP}}&gpp_sid={{.GPPSID}}