Add failed state to Entity screen

[luizgrp]

WHAT

Add failed state to EntityScreen.

Also fix layout of dialog of UampPlaylistsScreen, as the button wasn't centred as per preview in #490.

WHY

In order to have design closer to Figma specs.
In order to have user journey aligned with Figma specs.

HOW

• Change ViewModel to emit a "failed" state for any exception;
• Change screen to display a dialog on Failed state;
• Add onErrorDialogCancelClick param to screen so it can navigate back when the dialog is dismissed;

Checklist 📋

• Add explicit visibility modifier and explicit return types for public declarations
• Run spotless check
• Run tests
• Update metalava's signature text files