feat(display-edit): disable delete depending on cardinality (DSP-1814)

[mdelez]

resolves DSP-1814

[mdelez]

@kilchenmann should we remove the delete button from the UI in the event the user cannot delete the value or should we disable the button with a hint why it can't be deleted?

[kilchenmann]

@kilchenmann should we remove the delete button from the UI in the event the user cannot delete the value or should we disable the button with a hint why it can't be deleted?

We should disable it. Because the user expects the button. It could be confusing if the button is there in some cases but in other cases not.
Btw if the button is disabled the matTooltip will not work. In this case you have to surround (?) it with span tags, where you add the matTooltip. Here's an example how I did it in the ontology-editor: https://github.com/dasch-swiss/dsp-app/blob/fb6c36890f78ea7612f86c2a2978d9c6908b890d/src/app/project/ontology/ontology.component.html#L103 (Lines 103-109)

[kilchenmann]

LGTM 🚀