Use vue-test-utils for application row tests

What does this MR do?

The tests for the <application-row> component are still using the deprecated helpers/vue_mount_component_helper. This MR is to switch it to use vue-test-utils instead. Please note that the scope of this MR is only to switch to vue-test-utils, and aside from some low-hanging fruit, it does not and is not intended to address the robustness of the tests themselves.

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• [-] Style guides
• [-] Database guides
• [-] Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done