MATTER-5424 : enable CLA

[Sarthak-Shaha]

Description

Need to enable CLA for all public repos.
Following directions from https://confluence.silabs.com/spaces/GU/pages/610375348/CLA+Assistant+Lite+-+Contributor+License+Agreement

Related Issue

MATTER-5424

Changes Made

• Enable CLA checks trigger for each PR
• security improvement: Added masking for secrets
• Using ubuntu-latest

Checklist

• I have read the Contributor License Agreement.
• I have followed the repository's coding guidelines .
• I have checked the action workflow results and they are all passed.

Screenshots (if applicable)

Additional Notes

[Copilot]

Pull Request Overview

This PR enables Contributor License Agreement (CLA) validation for public repositories by configuring a GitHub workflow to automatically check CLA status on pull requests and comments.

• Activates CLA checking triggers for pull requests and issue comments
• Enhances security by masking sensitive tokens in workflow logs
• Updates runner environment to use the latest Ubuntu version

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