[iOS] signin target cleanup

Removing //ios/chrome/browser/ui/authentication/signin:signin_protected
from //ios/chrome/browser/ui/settings/google_services.

This dependency is not used anymore.

Change-Id: I543b9c129441bfa8b39d3cf16c6fd4aaeab2247e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2626389Reviewed-by: Nohemi Fernandez <fernandex@chromium.org>
Commit-Queue: Nohemi Fernandez <fernandex@chromium.org>
Auto-Submit: Jérôme Lebel <jlebel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#843530}

ios/chrome/browser/ui/settings/google_services/BUILD.gn

@@ -61,7 +61,6 @@ source_set("google_services") {
     "//ios/chrome/browser/ui/authentication",
     "//ios/chrome/browser/ui/authentication/cells",
     "//ios/chrome/browser/ui/authentication/signin:signin_headers",
-    "//ios/chrome/browser/ui/authentication/signin:signin_protected",
     "//ios/chrome/browser/ui/commands",
     "//ios/chrome/browser/ui/coordinators:chrome_coordinators",
     "//ios/chrome/browser/ui/icons",