message: tests(PanelHeaderButton): add Component tests
diff: import { baselineComponent } from '../../testing/utils';
  -import { PanelHeaderButton } from './PanelHeaderButton';
  +import { PanelHeaderButton, PanelHeaderButtonProps } from './PanelHeaderButton';
  +import { render, screen } from '@testing-library/react';
  +
  +const PanelHeaderButtonTest = (props: PanelHeaderButtonProps) => (<PanelHeaderButton data-testid="button" {...props} />);
  +const button = () => screen.getByTestId('button');
  describe('PanelHeaderButton', () => {
  baselineComponent(PanelHeaderButton);
  +
  + it('Component: default PanelHeaderButton is a button', () => {
  + render(<PanelHeaderButtonTest />);
  + expect(button().tagName.toLowerCase()).toMatch('button');
  + });
  +
  + it('Component: PanelHeaderButton w/ href is a link', () => {
  + render(<PanelHeaderButtonTest href="https://vk.com" />);
  + expect(button().tagName.toLowerCase()).toMatch('a');
  + });
  +
  + it('Component: PanelHeaderButton does not react to passed Component', () => {
  + render(<PanelHeaderButtonTest href="https://vk.com" Component="div" />);
  + expect(button().tagName.toLowerCase()).toMatch('a');
  + });
  });
  