Replace deprecated .is() with alternate approaches

What does this MR do?

@vue/test-utils 1.x deprecated .is()

.is() is used to assert wrapper against CSS selector or component class. This MR addresses first case (matching against CSS selector

Screenshots

N/A

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