Samples/button ux

[WispyMouse]

Improved Player Data Storage and Title Data Storage samples by giving their buttons interactive states. They'll automatically become not interactable, or become interactable again, when the passed conditions are met.

Please give feedback on:

• Is this the appropriate way to set up an event?
• Is this an appropriate way to call the event?
• Is this an appropriate way to subscribe to the event?
• Is this style of referencing buttons breaking any fundamental UI philosophy?
• What do y'all think about the [SerializeReference] attribute? The purpose is to not expose the UX buttons at a public level, but by being a SerializeReference field it can still be set in the editor.

#EOS-2149