Allow acl in mqtt when client certificate is in use

[GMagician]

Acl in mqtt needs user name if 'use_identity_as_username/use_subject_as_username' is not true. It also seems that login in mqtt doesn't accept an user with an empty password, then reenabled both

Checklist:

• The pull request is done against the latest development branch
• Only relevant files were touched
• Only one feature/fix was added per PR and the code change compiles without warnings
• The code change is tested and works with Tasmota core ESP8266 V.2.7.8
• The code change is tested and works with Tasmota core ESP32 V.3.1.1.250203
• I accept the CLA.

[s-hadinger]

The problem here is that Tasmota sets non-empty user/password for MQTT. This change would immediately break any existing configuration when using Client Certificate, and not setting user/password to empty strings.

I'm afraid there should be some option or additional setting to force user/password when using client cert

[GMagician]

The problem here is that Tasmota sets non-empty user/password for MQTT. This change would immediately break any existing configuration when using Client Certificate, and not setting user/password to empty strings.

I'm afraid there should be some option or additional setting to force user/password when using client cert

I missed this....sorry. maybe may I recycle INCLUDE_LOCAL_CERT?

[GMagician]

Replaced by #22998