Cp-ansible: Exception SASL SCRAM User when password is vaulted

Describe the issue

Using your playbook with sasl_protocol to scram. If you set user password vaulted, you have an exception in this task :
fatal: [XXXXXXX]: FAILED! => {"msg": "An unhandled exception occurred while templating '{{ kafka_broker_combined_properties | combine(kafka_broker_custom_properties) }}'. [....] can only concatenate str (not \"AnsibleVaultEncryptedUnicode\") to str"}

I think problem raise from combine_properties function because in default configuration password is string. So if password is vault encode myabe fix it with 'toString() python method' :

    def combine_properties(self, properties_dict):
        # Loops over master properties dictionary and combines sub elements if enabled
        final_dict = {}
        for prop in properties_dict:
            if properties_dict[prop].get('enabled'):
                final_dict.update(properties_dict[prop].get('properties'))
        return final_dict

To Reproduce
All Vars Configuration :

    sasl_protocol: scram

    sasl_scram_users:
      admin:
        principal: "admin"
        password: !vault |
          $ANSIBLE_VAULT;1.1;AES256
          32313537636131333038303532613231653233343565303831396530393061643031303432303632
          6537306234393563343861643834336430353930643062370a663563376131653664653430363963
          62303339313937646635663032326266383439623736623462373632313934643261303634663732
          3331643634623337610a616365613231346630656564616265656231633238313932333437363461
          65626165666531656463353562323165376135653631316435653337366164653063
      client:
        principal: "client"
        password: !vault |
          $ANSIBLE_VAULT;1.1;AES256
          35653666663833386164616630353966363231633234633561663464653931393835653830303630
          3263373337396137653637383332656539373766346438370a353164383737306535646234363065
          66643863353439663064346564333062373265653036646137306531353336323931653931363032
          3231373831366531640a323161386538333966646635353462623263346234306631383635646237
          34613764663736346362616562623061333438613461616162386532373266393166

Workaround

A workaround exist, you need to convert vault encoded string :

    sasl_protocol: scram

    sasl_admin_password: !vault |
      $ANSIBLE_VAULT;1.1;AES256
      32313537636131333038303532613231653233343565303831396530393061643031303432303632
      6537306234393563343861643834336430353930643062370a663563376131653664653430363963
      62303339313937646635663032326266383439623736623462373632313934643261303634663732
      3331643634623337610a616365613231346630656564616265656231633238313932333437363461
      65626165666531656463353562323165376135653631316435653337366164653063

    sasl_client_password: !vault |
      $ANSIBLE_VAULT;1.1;AES256
      35653666663833386164616630353966363231633234633561663464653931393835653830303630
      3263373337396137653637383332656539373766346438370a353164383737306535646234363065
      66643863353439663064346564333062373265653036646137306531353336323931653931363032
      3231373831366531640a323161386538333966646635353462623263346234306631383635646237
      34613764663736346362616562623061333438613461616162386532373266393166

    sasl_scram_users:
      admin:
        principal: "admin"
        password: "{{sasl_admin_password|string}}"
      client:
        principal: "client"
        password: "{{sasl_client_password|string}}"