Global Settings; Branch and External Party "Client Type" should only allow Organisation types

The following changes have been made to Global Settings:

1. Branches group, General page, Client Type is now limited to Organisation Client Types.

2. External Parties group, General page, Client Type is now limited to Organisation Client Types.

In addition, the message shown if the default Client Type was an Individual when adding a Branch was "Client Type cannot be changed for a Client linked to a Branch.". The message has been updated to "Branch Client must be an Organisation.". The same issue applied to External parties.