Bootstrap animation backend gtests for the commit hook (#56208)

Summary:

Added gtests for the `AnimationBackendCommitHook`, covering animation prop application during shadow tree commits.

## Changelog: 
[Internal][Added] - Added unit tests for AnimationBackendCommitHook

Differential Revision: D85753532

Author: Bartlomiej Bloniarz

packages/react-native/Package.swift

@@ -432,6 +432,7 @@ let reactFabric = RNTarget(
   path: "ReactCommon/react/renderer",
   excludedPaths: [
     "animated/tests",
+    "animationbackend/tests",
     "animations/tests",
     "attributedstring/tests",
     "core/tests",

packages/react-native/ReactCommon/React-Fabric.podspec

@@ -71,6 +71,7 @@ Pod::Spec.new do |s|
 
   s.subspec "animationbackend" do |ss|
     ss.source_files         = podspec_sources("react/renderer/animationbackend/**/*.{m,mm,cpp,h}", "react/renderer/animationbackend/**/*.{h}")
+    ss.exclude_files        = "react/renderer/animationbackend/tests"
     ss.header_dir           = "react/renderer/animationbackend"
   end