Performers filled in multiple values of TPE1 does not visible in "All artists"
When importing tracks with both TPE1 and TPE2 filled in, Lollypop ignores TPE1 performers.
As result these performers not listed in "All artists" list. + for example: page for Tarja Turunen will not contain "Scorpions - Good Die Young ft. Tarja Turunen" or Dido's page will not contain "Eminem - Stan ft. Dido"