Coalesce RepeatInstance and Group if group is the only child of RepeatInstance

[sadiqkhoja]

Current ui-vue handles this logic. This should be move inside the engine.

Ref: #69 (comment)

const label = computed(() => {
	// It has just one child and that is a group with label
	// then we use label of that group
	if( props.instance.currentState.children.length === 1 && 
		isGroup(props.instance.currentState.children[0]) && 
		props.instance.currentState.children[0].currentState.label
	) {
		return props.instance.currentState.children[0].currentState.label?.asString
	}
	// Use RepeatRangeNode label if it's there
	// TODO/sk: use state.label.asString
	if(props.instance.parent.definition.bodyElement.label?.children[0]?.stringValue){
		return `${props.instance.parent.definition.bodyElement.label?.children[0].stringValue} ${props.instanceIndex + 1}`;
	}
	return `Repeats ${props.instanceIndex+1}`;
});
const children = computed(() => {
	// It has just one child and that is a group
	// then we use its children - essentially coalesce RepeatInstance and Group into one.
	if(props.instance.currentState.children.length === 1 && isGroup(props.instance.currentState.children[0])){
		return (props.instance.currentState.children[0] as GroupNode).currentState.children;
	}
	else{
		return props.instance.currentState.children;
	}
});