[iOS] Update Chromium OWNERS for Chrome sign-in iOS.

Streamlines the existing OWNERS files and adds fernandex@ to sign-in.

Bug: 1060993
Change-Id: I20e91d74fc6d6013904aa5d9faea502b1ee66985
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2098629
Auto-Submit: Nohemi Fernandez <fernandex@chromium.org>
Reviewed-by: Jérôme Lebel <jlebel@chromium.org>
Commit-Queue: Jérôme Lebel <jlebel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#749671}

components/signin/ios/OWNERS

+fernandex@chromium.org
 jlebel@chromium.org
 msarda@chromium.org
 

ios/chrome/browser/first_run/OWNERS

-jlebel@chromium.org
-msarda@chromium.org
+file://components/signin/ios/OWNERS
 
 # COMPONENT: UI>Browser>FirstRun
 

ios/chrome/browser/signin/OWNERS

-jlebel@chromium.org
-msarda@chromium.org
+file://components/signin/ios/OWNERS
 
 # COMPONENT: Services>SignIn
 

ios/chrome/browser/ui/authentication/OWNERS

-jlebel@chromium.org
-msarda@chromium.org
+file://components/signin/ios/OWNERS
 
 # COMPONENT: Services>SignIn
 

ios/chrome/browser/ui/first_run/OWNERS

-jlebel@chromium.org
+file://components/signin/ios/OWNERS
+
 kkhorimoto@chromium.org
 
 # TEAM: ios-directory-owners@chromium.org

ios/chrome/browser/ui/signin_interaction/OWNERS

-jlebel@chromium.org
-msarda@chromium.org
+file://components/signin/ios/OWNERS
 
 # COMPONENT: Services>SignIn
 

ios/chrome/browser/unified_consent/OWNERS

-msarda@chromium.org
-jlebel@chromium.org
+file://components/signin/ios/OWNERS
 
 # TEAM: chrome-signin@chromium.org
 # COMPONENT: Services>SignIn

ios/public/provider/chrome/browser/signin/OWNERS

-jlebel@chromium.org
-msarda@chromium.org
+file://components/signin/ios/OWNERS
 
 # COMPONENT: Services>SignIn