Add missing viewtransition subdirectory to Fantom tester CMakeLists (facebook#55887)

Summary:
The ViewTransitionModule commit (f81f73e) added `react_renderer_viewtransition` as a dependency of `react_renderer_scheduler`, but did not update the Fantom tester's `CMakeLists.txt` to include the `react/renderer/viewtransition` subdirectory. This causes the Fantom tester build to fail with:

```
/usr/bin/ld: cannot find -lreact_renderer_viewtransition: No such file or directory
```

This adds `add_react_common_subdir(react/renderer/viewtransition)` to the Fantom tester CMakeLists.

Changelog: [Internal]

Pull Request resolved: facebook#55887

Test Plan: - `run_fantom_tests` CI should pass with this fix.

Reviewed By: cipolleschi

Differential Revision: D95066938

Pulled By: cortinico

fbshipit-source-id: aeda33365d9967fa7a3e07ac57c4a86863f20243

Author: cortinico

private/react-native-fantom/tester/CMakeLists.txt

@@ -105,6 +105,7 @@ add_react_common_subdir(react/renderer/scheduler)
 add_react_common_subdir(react/renderer/telemetry)
 add_react_common_subdir(react/renderer/textlayoutmanager)
 add_react_common_subdir(react/renderer/uimanager)
+add_react_common_subdir(react/renderer/viewtransition)
 add_react_common_subdir(react/renderer/uimanager/consistency)
 add_react_common_subdir(react/runtime)
 add_react_common_subdir(react/runtime/hermes)