[iOS] Allow use of extra entitlements for EG tests.

ios/chrome/test/earl_grey/chrome_ios_eg_test.gni

Index: ios/chrome/test/earl_grey/chrome_ios_eg_test.gni
diff --git a/ios/chrome/test/earl_grey/chrome_ios_eg_test.gni b/ios/chrome/test/earl_grey/chrome_ios_eg_test.gni
index c5d7fb91f3cadd5444340925605dc2dd1904c13d..9e55660fb998e8f58a545570c60bfa8621e34ca5 100644
--- a/ios/chrome/test/earl_grey/chrome_ios_eg_test.gni
+++ b/ios/chrome/test/earl_grey/chrome_ios_eg_test.gni
@@ -53,6 +53,9 @@ template("chrome_ios_eg_test") {
       output_name = "$target_gen_dir/$_target_name.entitlements"
       plist_templates =
           [ "//ios/chrome/test/earl_grey/resources/Chrome.entitlements" ]
+      if (ios_chrome_entitlements_additions != []) {
+        plist_templates += ios_chrome_entitlements_additions
+      }
     }
   }