Update psmdt.sql

[MrBerkk]

resolves the PRIMARY KEY must be NOT NULL error during database initialization by updating the mdt_data table schema.

Pull Request Checklist

• [ x] PR is targeting the dev branch
• [ x] I have pulled the latest changes from dev and resolved any merge conflicts
• [ x] My code follows the project’s style guidelines
• [ x] I have tested my changes and ensured they work as expected
• [ x] Relevant documentation/comments have been added or updated
• Any dependent changes have been merged

Description

This PR fixes a critical error encountered when initializing the database schema on a clean MySQL server, specifically the constraint violation where a Primary Key column was defined as DEFAULT NULL.

• Changed the cid column definition from VARCHAR(20) DEFAULT NULL to VARCHAR(20) NOT NULL.

Related Issues

Testing Steps

1. Running the SQL file (psmdt.sql) on a fresh Ubuntu Server with MySQL 8.0.
2. Confirming the table mdt_data was created successfully without the PRIMARY KEY must be NOT NULL error.

Additional Notes