* [CHD-3984] [Support Center/Security] A banned email address can no longer be used to sign in to the Support Center.
* [CHD-3984] [Support Center/Security] A banned email address can no longer be used to register an account in the Support Center.
* [Support Center/Security] A banned email address can no longer be added as an alternate to an existing account in the Support Center.
* [CHD-3984] [Support Center/Security] A banned email address can no longer be used to recover an account login in the Support Center.
[Code Cleanup]
Merge branch '6.8.7' into stable