Fix PhishGuard link

Author: Maddy-Cloudflare

public/__redirects

@@ -2443,6 +2443,7 @@
 /cloudflare-one/email-security/detection-settings/configure-text-add-ons/ /cloudflare-one/email-security/settings/detection-settings/configure-text-add-ons/ 301
 /cloudflare-one/email-security/reference/domain-information/ /cloudflare-one/email-security/settings/domain-management/domain/ 301
 /cloudflare-one/insights/email-monitoring/phish-submissions/* /cloudflare-one/email-security/settings/phish-submissions/:splat 301
+/cloudflare-one/email-security/phish-guard/* /cloudflare-one/email-security/phishguard/:splat 301
 
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