Feature: #99608 - Add password policy action to exclude validators in SU mode 

See forge#99608

Description 

The new password policy action UPDATE_USER_PASSWORD_SWITCH_USER_MODE has been added in order to allow administrators to exclude a password policy validator, if the current user is in switch user mode.

The new password policy action is used in the global default password policy for the NotCurrentPasswordValidator.

Impact 

When the current backend user is in switch user mode, it is not validated, if the new password equals the current user password in ext:setup.