[Email Security] Fix broken links + remove duplicate page

Author: Maddy-Cloudflare

src/content/docs/cloudflare-one/email-security/investigation/search-email.mdx

@@ -277,4 +277,4 @@ Mail trace allows you to track the path your selected message took from the send
 
 - **Date**: The date and time when the mail was tracked.
 - **Type**: An email can be inbound (email sent to you from another email), or outbound (emails sent from your email address).
-- **Activity**: The activity taken on an email. For example, moving the email to the trash folder, releasing a quarantined email, and more.
+- **Activity**: The activity taken on an email. For example, moving the email to the trash folder, releasing a quarantined email, and more.

src/content/docs/cloudflare-one/email-security/monitoring/search-email.mdx

@@ -1,6 +1,6 @@
 ---
 pcx_content_type: navigation
-title: Invalid submissions
+title: Invalid submissions emails
 sidebar:
   order: 5
   group: