Fix Karma Unit Tests (support/0.x)

[rthaut]

Description

This PR fixes the Karma unit tests for the support/0.x branch. Specifically, the checks for the has-error and has-success classes were targeting the wrong DOM nodes.

Checklist

• [x] I have read and understand the CONTRIBUTIONS.md file
• [x] I have searched for and linked related issues
• [x] I have created test cases to ensure quick resolution of the PR is easier
• [x] I am NOT targeting main branch
• [x] I did NOT include the dist folder in my PR

@json-schema-form/angular-schema-form-lead