Change modal title

[deletidev]

If you create a new relation, the title of the modal is "Edit relation", it changes only in this case with the text "Add relation". As in add collection modal it has different titles depending on where you click.

This modal opens when you click an add relationship button, in src/pods/toolbar/components/relation-button.component.tsx, we have to add a new const where we have the other const for the modal title with the value "Add relation".