Add check the code is run on the Node entity page

[NightHunterSV]

We should check before, that the node is a Drupal\node\NodeInterface, or, at least, FieldableEntityInterface. We've got the error on this string at some project, where the route's 'node' parameter is a string.

https://github.com/ymcatwincities/openy_gated_content/blob/50dfae4a8970cceb8529612f6c29dad849296d78/openy_gated_content.module#L112

[anpolimus]

@NightHunterSV thank you. You are totally right.

[sarah-halby]

@anpolimus what is the estimate for this fix and what are the next steps?

[anpolimus]

@sarah-halby we will do it in scope of our current ticket.

[anpolimus]

@sarah-halby here is the fix ^^

[sarah-halby]

@anpolimus & @hamrant are we good to close this ticket then?

[hamrant]

@sarah-halby yep