chore: Support plus forwarding in email channel (#6482)

- Support for plus forwarding in the email addresses for email channels

Co-authored-by: Sojan <sojan@pepalo.com>

app/helpers/email_helper.rb

@@ -3,4 +3,11 @@ module EmailHelper
     domain = email.split('@').last
     domain.split('.').first
   end
+
+  # ref: https://www.rfc-editor.org/rfc/rfc5233.html
+  # This is not a  mandatory requirement for email addresses, but it is a common practice.
+  # john+test@xyc.com is the same as john@xyc.com
+  def normalize_email_with_plus_addressing(email)
+    "#{email.split('@').first.split('+').first}@#{email.split('@').last}".downcase
+  end
 end