PHILADELPHIA — On a team that is deep and proven in most areas, opportunities for young, unproven players to break through with the Eagles are limited. Still, a few intriguing candidates are worth watching closely through the spring and summer. When identifying potential breakout players, the first step is finding real opportunity. It’s no surprise, then, that the three names below project as potential contributors at safety, along the interior offensive line, and at wide receiver — a position where Philadelphia is expected to enter a post-A.J. Brown era after June 1. DB Brandon Johnson An undrafted free agent out of Oregon last year, Johnson is a forgotten name who was quietly gaining traction with the coaching staff by the end of the season. The slot/safety versatility Johnson brings fits perfectly with Vic Fangio’s defense .…