[BE] [Bug] Instance Admins could not create groups when allow_project_creation_for_guest_and_below was disabled

Bug:

Instance Admins who do not have any group/projects created by them cannot create groups/projects when allow_project_creation_for_guest_and_below setting is turned off.

Analysis:

When setting allow_project_creation_for_guest_and_below is turned off

• allow_user_to_create_group_and_project? relies on highest_role
• highest_role is filled from current_highest_access_level
• current_highest_access_level gets the maximum access_level a user has in the members table.
• For Instance Admins who have not created any groups before turning the setting off(typical for new installations) ----> here is the bug
  • they would not have any entry in the members table
  • highest_role would return NO_ACCESS for them
  • and allow_user_to_create_group_and_project? would return false
• For Instance Admins who have created some groups before turning the setting off
  • they would have any entry in the members table
  • highest_role would return OWNER
  • allow_user_to_create_group_and_project? would return true