VID-1993 Fixed broken Selenium tests

* Need to wait for elements to appear before testing them
* Was not swapping video before trying to undo a swap

https://wikia-inc.atlassian.net/browse/VID-1993
LicensedVideoSwap_003_swap() test fails for me locally on Chrome, because it can't see firstSwapButton element. Adding scrolling method, e.g. replacing 'firstSwapButton.click();' with 'scrollAndClick(firstSwapButton);' solves problem for me, could you check it?