Remove link if no parent is available

@FineX: what have you chosen for "Link image to" in display configuration for this media type?

Parent content if I remember correctly.

I suppose if you choose "Nothing" for "Link image to" you will receive no link in the case you describe.

The link to the media edit page is the default from Drupal core I suppose and media parent entity link will only come into play if there is a parent entity and this parent entity has a canonical link.

So I think if you choose "Nothing" for "Link image to" and still check the box "Link to parent entity (if appicable)" you may get the same output that would come with your patch.

tending to close this with "works as designed", if you do not have any more comments on this.