Matter: Add RGB+CCT Light5 support

[gudinis]

Description:

Add Matter support for 5-channel RGB+CCT lights through a new light5 plugin.

Matter autoconfiguration currently supports 1-channel (dimmable), 2-channel (color temperature), and 3-channel (RGB) lights, while 5-channel lights are explicitly left unsupported.

This PR adds support for 5-channel RGB+CCT devices as a single Matter Extended Color Light endpoint, supporting both Hue/Saturation and Color Temperature control.

Changes:

• Add Matter_Plugin_Light5 for RGB+CCT lights.
• Support Hue/Saturation and Color Temperature through the Matter Color Control cluster.
• Add light5 to the Matter UI plugin types.
• Automatically detect 5-channel local lights as light5.
• Add the Light5 plugin to the Matter module.

Tested on an ESP32-C3 5-channel RGB+CCT bulb with Tasmota core ESP32 V.3.3.8 / Platform 2026.05.50.

Verified:

• On/Off
• Brightness
• Hue/Saturation control
• Color Temperature control
• Switching between RGB and Color Temperature modes
• Matter state feedback
• State restoration after reboot/power cycle
• Automatic 5-channel detection as light5

Related issue (if applicable): N/A

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.3.3.8 from Platform 2026.05.50
• I accept the [CLA](https://github.com/arendst/Tasmota/blob/development/CONTRIBUTING.md#contributor-license-agreement-cla).

NOTE: The code change must pass CI tests. Your PR cannot be merged unless tests pass