Justin has always been good friends with the Kardashians, so he and Kendall go way back, said a source.There have been rumours about them dating before and it was even suggested that Kendall played a part in his break-up with Selena Gomez, added the source.Bieber, who was partying with stars including Kate Moss, P. Diddy, Jared Leto and Kanye West at the bash, is said to have had his eyes on th