no-self-import doesn't account for path "grandparents"

[JoshuaKGoldberg]

Two errors discovered in DefinitelyTyped/DefinitelyTyped#66522 are a result of upgrading from the TSLint no-self-import implementation to the ESLint @definitelytyped/no-self-import implementation from #652:

2> /home/runner/work/DefinitelyTyped/DefinitelyTyped/types/chrome/har-format/index.d.ts
2>   1:1  error  Declaration file should not use a global import of itself. Use a relative import  @definitelytyped/no-self-import

from:

import { Entry, Log } from 'har-format';

...and...

1> /home/runner/work/DefinitelyTyped/DefinitelyTyped/types/openfin/v50/_v2/api/events/emitterMap.d.ts
1>   2:1  error  Declaration file should not use a global import of itself. Use a relative import  @definitelytyped/no-self-import

from:

```ts
import { EventEmitter } from 'events';