Earpiece assembly removal not attached to screen

You've made a common mistake in removing the screen, which consists of separating the screen's mounting frame from the screen instead of the phone. On OEM screens this mostly happens when you forget to remove the Pentalobe screws at the bottom of the phone, but I've seen it happen on aftermarket displays where they didn't use a good grade of adhesive on the screen frame.

The fix is fairly simple; just repeat the screen removal procedure on the frame this time; go around the edge of the phone and pry up the metal frame that's been left on the phone instead of coming off with the screen. That'll release the front sensor assembly as well and you'll be able to unplug it.

No harm done since you're replacing the screen anyway, so don't worry about it, just transfer the front sensors to the new screen once you get the frame off and you'll be good to go.