Increase converage and add gitlab tests

[erseco]

This pull request introduces a comprehensive set of new unit tests for critical components of the Documentate plugin, focusing on export handlers, the admin converter template, and the uninstall process. Additionally, it updates the SonarQube scanner version in CI. These changes significantly improve test coverage, ensuring that key functionality, security checks, and integration points are properly validated.

Testing improvements

• Added ExportHandlerTest to verify the behavior of Export_Handler and its subclasses (Export_DOCX_Handler, Export_ODT_Handler, Export_PDF_Handler), including format/mime type methods, input sanitization, permission checks, and class structure.
• Added DocumentateConverterTemplateTest to ensure the admin/documentate-converter-template.php file contains all required HTML, PHP variables, JavaScript integrations (including ZetaJS), AJAX handling, error handling, and CSS styles.
• Added UninstallTest to check the existence and security of the uninstall.php file, verifying the presence of guard clauses and correct behavior when the uninstall constant is defined.

CI/CD update

• Updated SonarQube scanner CLI image version from 11.4 to 11.5 in .gitlab-ci.yml to ensure the latest static analysis tooling is used.

[chatgpt-codex-connector]

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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