Admin rejecting account request: give actual account in the email template

[damithc]

When the admin is rejecting an account request using 'reject with reason' option, one of the possible reasons is that there is already an account for that email. In that case, the user is suggested to login using the existing account.

Current: the suggested login account is the same as the email address specified in the account request Suggested:

1. Specify the Google account of the user instead, as that's what the user needs to use to login

2. Add the following info to the instructions.

   If you are logged into multiple Google accounts, remember to logout from other Google accounts first, or use an incognito Browser window. Let us know (with a screenshot) if that doesn't work.