Update kap-plugin tests for new conf version (#46846)
Update kap-plugin tests for new conf version (#46846)

The new version makes the type of `get` stricter by fixing a `string |
<string subtype>` union. This makes the return type of `get` not include
`undefined`.
georgemarshall/DefinitelyTyped,georgemarshall/DefinitelyTyped,georgemarshall/DefinitelyTyped,markogresak/DefinitelyTyped,georgemarshall/DefinitelyTyped,mcliment/DefinitelyTyped