chore(test): add e2e tests for tabs bottomAccessory on iOS

[LKuchno]

Description

This PR adds automated Detox e2e test coverage for the bottomAccessory prop on TabsHost (iOS-only, requires iOS 26+). The new Detox suite (test-tabs-bottom-accessory-ios.e2e.ts) covers initial render, variant switching, accessory persistence across tab changes, and the extended-to-inline layout transition driven by scroll direction. A scenario.md was updated in e2e section wth information what was automated and what wasn't.

Changes

• FabricExample/e2e: Add test-tabs-bottom-accessory-ios.e2e.ts - a Detox iOS-only suite with test cases covering accessory render, variant updates, cross-tab persistence, and scroll-driven layout transitions (extended ↔ inline)
• apps/tests/tabs: Restructured test-tabs-bottom-accessory-layout-ios/ directory; add testID props to all accessory views, variant cards, and scroll items; add ScrollDownTab and ScrollUpTab components; auto-scroll ScrollUpTab to bottom on mount so the scroll-up direction is meaningful for minimize behavior testing
• apps/tests/tabs: Update scenario.md with e2e automation info

[Copilot]

Pull request overview

Adds an iOS-only Detox e2e suite and a dedicated single-feature-test scenario screen to validate TabsHost’s bottomAccessory behavior (including persistence across tabs and transitions between extended vs inline layouts driven by tabBarMinimizeBehavior).

Changes:

• Added a new iOS Detox suite covering accessory rendering, variant switching, persistence across tab changes, and scroll-driven layout transitions.
• Replaced the old placeholder scenario with a new instrumented 3-tab scenario screen (Config / ScrollDown / ScrollUp) and added testIDs needed for reliable Detox selectors.
• Updated tabs scenario registration to point to the new scenario module and added a written manual test plan (scenario.md).

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
FabricExample/e2e/single-feature-tests/tabs/test-tabs-bottom-accessory-ios.e2e.ts	New iOS Detox suite exercising bottom accessory variants, persistence, and scroll-driven layout transitions.
apps/src/tests/single-feature-tests/tabs/test-tabs-bottom-accessory-layout-ios/scenario.md	Documents manual + automated coverage and iPad-specific notes.
apps/src/tests/single-feature-tests/tabs/test-tabs-bottom-accessory-layout-ios/index.tsx	New 3-tab test scenario screen with runtime host-config updates and testIDs for e2e.
apps/src/tests/single-feature-tests/tabs/index.ts	Registers the new scenario module in the Tabs single-feature-tests group.
apps/src/tests/single-feature-tests/tabs/bottom-accessory-layout.tsx	Removes the previous placeholder scenario implementation.

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[LKuchno]

Problem with not collapsing tab bar (tabBarMinimizeBehavior) which lead to TestiOS e2e failure is fixed when changes from this PR are applied:
https://github.com/software-mansion/react-native-screens/pull/4004/changes