[iOS 26] Switch with custom thumb color is losing color when coming back to app

Description

Using iOS 26, when you give a switch custom thumb colors, go to another app, come back to your app, then the custom colors are lost.

Steps to reproduce

1. Install the application on iOS 26.
2. Enable one of the toggles.
3. Switch app and come back.
4. Thumbs of switches which used to have a custom thumb color are white.

React Native Version

0.81.4

Affected Platforms

Runtime - iOS 26

Output of npx @react-native-community/cli info

System:
  OS: macOS 15.6.1
  CPU: (12) arm64 Apple M2 Pro
  Memory: 129.11 MB / 32.00 GB
  Shell:
    version: "5.9"
    path: /bin/zsh
Binaries:
  Node:
    version: 22.18.0
    path: ~/.nvm/versions/node/v22.18.0/bin/node
  Yarn:
    version: 4.6.0
    path: ~/.nvm/versions/node/v22.18.0/bin/yarn
  npm:
    version: 10.9.3
    path: ~/.nvm/versions/node/v22.18.0/bin/npm
  Watchman:
    version: 2025.09.15.00
    path: /opt/homebrew/bin/watchman
Managers:
  CocoaPods:
    version: 1.15.2
    path: /Users/regina/.gem/ruby/3.2.2/bin/pod
SDKs:
  iOS SDK:
    Platforms:
      - DriverKit 25.0
      - iOS 26.0
      - macOS 26.0
      - tvOS 26.0
      - visionOS 26.0
      - watchOS 26.0
  Android SDK: Not Found
IDEs:
  Android Studio: 2024.3 AI-243.24978.46.2431.13363775
  Xcode:
    version: 26.0/17A324
    path: /usr/bin/xcodebuild
Languages:
  Java:
    version: 17.0.13
    path: /usr/bin/javac
  Ruby:
    version: 3.2.2
    path: /Users/regina/.rubies/ruby-3.2.2/bin/ruby
npmPackages:
  "@react-native-community/cli":
    installed: 20.0.0
    wanted: 20.0.0
  react:
    installed: 19.1.0
    wanted: 19.1.0
  react-native:
    installed: 0.81.4
    wanted: 0.81.4
  react-native-macos: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: true
  newArchEnabled: true
iOS:
  hermesEnabled: true
  newArchEnabled: true

Stacktrace or Logs

N/A

MANDATORY Reproducer

https://github.com/Regina-v/rn-ios26-switch-custom-color-bug

Screenshots and Videos

Screen record iOS 26: https://github.com/user-attachments/assets/33e01479-e9f7-4e29-9719-e9128a2ce1b9

Screen record iOS 18: https://github.com/user-attachments/assets/7b67f017-3ecd-46e7-accf-4b2773026c25

Inizia con il riproduttore obbligatorio all’indirizzo https://github.com/Regina-v/rn-ios26-switch-custom-color-bug e riproduci il comportamento dello switch su iOS 26, confrontandolo con iOS 18 come mostrato nel report. Traccia l’implementazione dello switch di React Native e verifica che i colori personalizzati del thumb rimangano dopo aver lasciato l’app e avervi fatto ritorno; il lavoro è completato quando la perdita di colore segnalata non si verifica più.