[pgAdmin4][Patch] - RM #6444 and #6445

#6444  - [Kerbores] - User is not warned if Kerberos ticket expiration is less than 30 min while initiating global backup.

#6445 - [Kerbores] - Kerberos Auth flag is True in properties dialogue though server is connected with password. 

There is no way to identify if the server connection is GSS authenticated or not. To solve this problem, I have introduced GSS authenticated? and GSS encrypted? fields in the server properties.

Thanks,

Khushboo