[MohamedRF]

Description
Reset shared services in SecurityHelperTest::setUp() so it does not reuse a request or security mock left by another helper test. With random seed 1793892530, SiteUrlCliTest runs first and leaves a CLIRequest in the shared request service. Constructing MockSecurity later fails because Security::$request requires an IncomingRequest.

Enable Helpers in the random-test configuration after verifying the component with the failing seed and repeated randomized runs. This completes the Helpers component of #9968; the overall issue remains open for other components.

Validation

• Before the fix: vendor/bin/phpunit tests/system/Helpers --order-by=random --random-order-seed=1793892530 --no-coverage fails with a CLIRequest/IncomingRequest TypeError.
• After the fix: the same command passes (577 tests, 984 assertions).
• Ten random component runs through .github/scripts/run-random-tests.sh --component Helpers --repeat 10 --max-jobs 2 --quiet pass.
• Deterministic seeds 1–10 pass.
• File-scoped PHP CS Fixer, Rector dry run, and PHPStan checks pass.
• git diff --check passes.

Tested with PHP 8.5.12 / PHPUnit 11.5.57 on macOS. The full platform matrix is left to CI.

Checklist:

• Securely signed commit
• Existing regression tests verified with the previously failing random seed
• Conforms to style guide
• PHPDoc and user guide changes: not applicable; this changes test isolation and CI coverage only.