ci: Bump Xcode & set device used for ui_tests_ios_swift6 (#5976)

* ci: Set device used for `ui_tests_ios_swift6`

* Bump Xcode to 16.4

Author: itaybre

.github/workflows/ui-tests.yml

@@ -106,7 +106,8 @@ jobs:
     uses: ./.github/workflows/ui-tests-common.yml
     with:
       fastlane_command: ui_tests_ios_swift6
-      xcode_version: 16.2
+      fastlane_command_extra_arguments: device:iPhone 16 (18.5)
+      xcode_version: 16.4
       build_with_make: true
       macos_version: macos-15
       codecov_test_analytics: true