Remove shadow DOM workaround when fixed in pay.js

[socsieng]

There's a workaround in place to handle when the button is used within a shadow DOM. This should ideally be fixed in pay.js. Once it is, this workaround should be removed.

google-pay-button/src/lib/button-manager.ts

Lines 346 to 373 in 5dfe00a

	// TODO(socsieng): #19 remove shadow DOM workaround when fixed in pay.js
	/**
	* workaround to get css styles into component
	*/
	private copyGPayStyles(): void {
	const node = this.element?.getRootNode();
	if (node && node instanceof ShadowRoot) {
	const styles = document.querySelectorAll('head > style');
	const gPayStyles = Array.from(styles).filter(s => s.innerHTML.indexOf('.gpay-button') !== -1);
	const existingStyles = new Set(
	Array.from(node.childNodes)
	.filter(n => n instanceof HTMLElement && n.nodeName === 'STYLE' && n.id)
	.map(n => (n as HTMLElement).id),
	);
	let index = 0;
	for (const style of gPayStyles) {
	index++;
	const id = `google-pay-button-style-${index}`;
	if (!existingStyles.has(id)) {
	const styleElement = document.createElement('style');
	styleElement.innerHTML = style.innerHTML;
	node.appendChild(styleElement);
	}
	}
	}
	}