fix: MQTT credentials are always set

[Teagan42]

Problem When authentication is disabled in EMQX, connection fails when username and password are defaulted to empty strings.

Description of Change

1. Default the MQTT credentials to undefined.
2. Check if username and password are truthy (non-null, defined, non-empty strings), if truthy apply username and password to MQTT options.
3. Check if username is truthy (non-null, defined, non-empty string), if truthy apply username to the clientId MQTT option.

[Luligu]

Hi, thank you for your interest and your PR.

I agree with you about passing undefined instead of empty strings for both username and password.

I'm not sure about passing username without password... that is really connected to a specific setup. Do you need it?

Let me just check that mosquito has no issues with that cause it is the 99% of uses.

Btw I cannot merge on the main... only on the dev. But wait that I check mqtt code and test mosquito before making a PR on the dev.

My best.

[Luligu]

[2.2.2] - 2024-10-22

Added

• [thermostat]: Added min_temperature_limit and max_temperature_limit converter.
• [thermostat]: Added min_heat_setpoint_limit and max_heat_setpoint_limit converter.

Changed

• [mqtt]: Username and password are passed like undefined unless set.
• [readme]: Updated install script.
• [readme]: Updated build script.
• [package]: Updated dependencies.
• [plugin]: Requires Matterbridge 1.6.1.

Fixed

• [thermostat]: Fixed the case when instead of current_heating_setpoint the property is occupied_heating_setpoint.
• [thermostat]: Fixed the case when instead of current_cooling_setpoint the property is occupied_cooling_setpoint.

Hi sorry for the late reply. I made it differently. If you have time to test it, would be nice. I tested it with mosquitto and all is correct. The tgz is in discord. https://github.com/Luligu/matterbridge/blob/main/CHANGELOG.md#discord