Re-fix isset check and revert PR #539

[bishopb]

Description of the change

Reverts commit 666a1a2, which altered the expected type of the reportSuppressed internal variable from boolean to the type of the user-supplied configuration value. Additionally, this allowed for potential malicious value injection, as the value of the configuration key was not checked.

Then, adds a test that exposes the bug associated with PR #539.

Finally, fixes said bug.

Type of change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Related issues

Checklists

Development

• Lint rules pass locally
• The code changed/added as part of this pull request has been covered with tests
• All tests related to the changed code pass in development

Code review

• This pull request has a descriptive title and information useful to a reviewer. There may be a screenshot or screencast attached
• "Ready for review" label attached to the PR and reviewers mentioned in a comment
• Changes have been reviewed by at least one other engineer
• Issue from task tracker has a link to this pull request