Replaced usage of toBeTruthy / toBeFalsy

What does this MR do and why?

Replaced Avoid usage of toBeTruthy with toBe(true) and toBeFalsy with toBe(false) in ee/spec/frontend/vue_shared/security_reports/components/dismissal_comment_box_toggle_spec.js

Resolves the issue

Screenshots or screen recordings

How to set up and validate locally

1. Navigate to gitlab directory
2. Run yarn jest spec/frontend/vue_shared/security_reports/components/dismissal_comment_box_toggle_spec.js

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #369786 (closed)