FIX: Make UI match server behavior for external-auth invites (#13113)

There are two methods which the server uses to verify an invite is being redeemed with a matching email:
  1) The email token, supplied via a `?t=` parameter
  2) The validity of the email, as provided by the auth provider

Only one of these needs to be true for the invite to be redeemed successfully on the server. The frontend logic was previously only checking (2). This commit updates the frontend logic to match the server.

This commit does not affect the invite redemption logic. It only affects the 'show' endpoint, and the UI.

app/controllers/invites_controller.rb

@@ -31,6 +31,11 @@ class InvitesController < ApplicationController
         end
       end
 
+      email_verified_by_link = invite.email_token.present? && params[:t] == invite.email_token
+      if email_verified_by_link
+        email = invite.email
+      end
+
       hidden_email = email != invite.email
 
       info = {
@@ -38,7 +43,8 @@ class InvitesController < ApplicationController
         email: email,
         hidden_email: hidden_email,
         username: hidden_email ? '' : UserNameSuggester.suggest(invite.email),
-        is_invite_link: invite.is_invite_link?
+        is_invite_link: invite.is_invite_link?,
+        email_verified_by_link: email_verified_by_link
       }
 
       if staged_user = User.where(staged: true).with_email(invite.email).first