fix(iOS, Tabs): add support for bottom accessory environment none

[johankasperi]

Description

When closing a bottomaccessory you get a RCTLogError with "Unsupported environment for onEnvironmentChange event". Thats because the environment is of type "none" when the bottom accessory is closed.

Changes

Add support for "none".

Screenshots / GIFs

Before

Simulator.Screen.Recording.-.iPhone.17.Pro.-.2025-11-20.at.15.56.26.mov

After

Uploading Simulator Screen Recording - iPhone 17 Pro - 2025-11-20 at 16.10.15.mov…

Test code and steps to reproduce

Run Test3288 and set shown to false using the button on the screen

Checklist

• Included code example that can be used to test this change
• Updated TS types
• Updated documentation:
  • https://github.com/software-mansion/react-native-screens/blob/main/guides/GUIDE_FOR_LIBRARY_AUTHORS.md
  • https://github.com/software-mansion/react-native-screens/blob/main/native-stack/README.md
  • https://github.com/software-mansion/react-native-screens/blob/main/src/types.tsx
  • https://github.com/software-mansion/react-native-screens/blob/main/src/native-stack/types.tsx
• Ensured that CI passes

[kkafar]

Thanks @johankasperi!

cc @kligarski

Will we need to update workarounds code?