[iOS][EG2] Enabling signin_interaction tests

Test converted with crrev.com/c/1958118

Bug: 866147
Change-Id: Ifbf25da1ce503dc834f0c11ceff5755f00985aaa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1978742Reviewed-by: Eugene But <eugenebut@chromium.org>
Commit-Queue: Jérôme Lebel <jlebel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#727095}

ios/chrome/test/earl_grey2/BUILD.gn

@@ -104,6 +104,7 @@ chrome_ios_eg2_test("ios_chrome_ui_eg2tests_module") {
     "//ios/chrome/browser/ui/safe_mode:eg2_tests",
     "//ios/chrome/browser/ui/settings/google_services:eg2_tests",
     "//ios/chrome/browser/ui/side_swipe:eg2_tests",
+    "//ios/chrome/browser/ui/signin_interaction:eg2_tests",
     "//ios/chrome/browser/ui/tab_grid:eg2_tests",
     "//ios/chrome/browser/ui/tabs:eg2_tests",
     "//ios/chrome/browser/ui/toolbar:eg2_tests",