Following her character’s surprising return in the recent Season 14 finale, Kim Raver is joining the veteran ABC medical drama full-time as a series regular for the upcoming 15th season. With its Season 15 renewal, the Shonda Rhimes-created Grey’s Anatomy, starring Ellen Pompeo and executive produced/showrun by Krista Vernoff, has become ABC’s longest-running primetime scripted series. Raver, who was previously a series regular on the ABC medical drama in Seasons 6-8…